Executive leadership

Roberto (Rob) Scenna

BEconomics (Hons), Advanced Management Program, Williamson Community Leadership Program

Chief Executive Officer

Roberto (Rob) joined Defence Bank as Chief Executive Officer in July 2024, bringing with him a wealth of financial and executive leadership experience from across the banking, wealth management and insurance sectors.

Prior to his appointment at Defence Bank, Rob was CEO of Catholic Church Insurance, MD of ANZ Private Bank, and the CEO of ANZ Trustees. In addition, he has also held senior leadership roles in ANZ Expatriate and Migrant Banking and Esanda Auto Finance.

Rob has a strong member and values driven focus. He leads through purposeful strategies that build organisational capability and support a meaningful connection with members. Rob has a deep understanding of people, processes, and technology, along with complex regulated environments.

In addition to his role at Defence Bank, Rob sits as Director of  the Italian Australian Foundation. He is a graduate of the Williamson Community Leadership Program.

Dean Barton

BCom, FFin, FCPA, GAICD

Chief Financial Officer

Dean joined Defence Bank as Chief Financial Officer in 2011. His primary responsibility is the Bank’s financial and regulatory reporting, management reporting and budgeting, funding and capital management. He also acts as Company Secretary to Defence Bank.

Dean has more than 20 years’ local and international experience in financial roles including Financial Controller for ME Bank, and Asia-Pacific Regional Financial Controller for GMAC Financial Services.

Dean is a Fellow of CPA Australia and the Financial Services Institute of Australasia, and a graduate member of AICD. Dean holds a BCom from the University of Western Australia majoring in Accounting and Economics.

Kristen Bugeja

BCom, CAHRI

Chief People Officer

Kristen Bugeja is a progressive HR executive with over 25 years of experience in the financial services sector. As Chief People Officer at Defence Bank, she leads the bank’s people and community strategy, driving organisational transformation and aligning culture, capability, and employee experience with strategic business outcomes.

A certified member of the Australian HR Institute, Kristen is known for her transformative leadership in cultural change, strategic workforce planning, and talent development. She has led impactful change across the organisation, transforming culture, and enhancing Defence Bank’s employee value proposition through purpose-driven reward and recognition programs that connect deeply to the bank’s values and purpose.

Kristen’s passion lies in creating exceptional employee experiences and building a workplace where people thrive. Under her leadership, Defence Bank has earned national recognition – winning Best Reward and Recognition Program and being named an Excellence Awardee for Employer of Choice at the 2024 Australian HR Awards.

Kristen continues to champion innovation, inclusion, and community engagement to ensure Defence Bank remains a truly great place to work – and a meaningful contributor to the communities it serves.

Marnie Fletcher

GAICD, INSEAD AMP, B.Arts, BCom, Grad Dip Applied Information Systems 

Chief Member and Marketing Officer 

Marnie Fletcher is a seasoned financial services executive with over 26 years of experience across Australia’s banking sector, including 17 years in major banks and the past 9 years in the customer-owned banking space. She is currently Chief Member & Marketing Officer at Defence Bank, where she leads the organisation’s Member division, encompassing Marketing, Branch and Lending Distribution, the Member Service Centre, Fraud and Scam Support, and Member Advocacy. 

Marnie is also a Board Member of the Customer Owned Banking Association (COBA), the industry body representing Australia’s customer-owned banking institutions. Her role reflects a deep commitment to purpose-led banking and the advancement of member-first financial services across the sector. 

Since joining Defence Bank in 2021, Marnie has spearheaded the transformation of the Bank’s lending ecosystem, delivering strong growth, operational efficiency, and a simplified experience for members and staff. She is committed to elevating the Bank’s brand and marketing strategy, ensuring it remains deeply connected to members while driving engagement, trust, and relevance in a competitive market. 

Throughout her career, Marnie has worked across a broad spectrum of customer segments – from institutional to retail – but her passion lies in supporting everyday Australians to make confident financial decisions and build better lives. Her leadership is defined by driving a balance between commercial outcomes, member outcomes, and purpose-led innovation.

Natalie Hannemann

BCom, BTeach 

Chief Experience and Product Officer 

Natalie joined Defence Bank as Chief Experience & Product Officer in August 2025. 

With over 25 years of leadership experience across financial services, health insurance and for-purpose sectors, Natalie brings a rich history shaped by working at the intersection of strategy, member experience, and enterprise delivery. 

Natalie has led transformational change across complex organisations, shaping enterprise strategy, evolving operating models, and delivering innovative services & experiences that meet the changing needs of members. 

As Chief Experience & Product Officer, Natalie is responsible for strategy, member experience, product development and management, digital innovation, analytics & insights and enterprise project delivery. She plays a key role in ensuring the organisation remains focused, data-informed and aligned to the needs of those it serves. 

With deep personal ties in the Defence community, Natalie brings a profound respect for the organisation’s purpose and a strong commitment to delivering meaningful outcomes for Defence members and their families. 

Sean O'Donnell

MBA, B.Bus, Dip Fin Adv, GAICD, SF Fin, FGIA, FACP, Chartered Banker 

Chief Technology Officer 

Sean joined Defence Bank as Chief Digital and Technology Officer in October 2023. He is an experienced senior executive and Non-Executive Director with extensive experience in the banking and technology sectors. He has held senior executive roles with global information technology firms and his banking career has seen him hold senior leadership roles in both major and regional banks. 

In his current role Sean leads Defence Bank’s Technology function. His team is focused on enabling Defence Bank’s digital transformation with an emphasis on member experience, risk management and information security. 

Sean strives to make a contribution to the wider community. He is an ambassador for Melbourne City Mission and its flagship fund raising event, Sleep at the ‘G. In addition he is an adjunct senior lecturer at Central Queensland University where he lectures on Banking and Finance as part of the University’s MBA program. 

Mirella Prasad

BA, Post Graduate Diploma Marketing 

Chief of Operations 

Mirella Prasad joined Defence Bank as Chief of Operations in August 2025. 

In this role, Mirella is responsible for Lending Operations, Member Operations, AML/CTF Operations and Corporate Operations. 

Mirella brings extensive experience in financial services and has a proven track record in leading complex organisations through transformation. Prior to this role, she has held senior Operations and Transformation roles at Transurban, Equifax, Bank of Queensland and GE.

Mirella has degrees in Applied Science and Marketing, and is a certified Lean Six Sigma Black Belt, Project Manager and Change Manager. Her proven Credit, Risk, Operations and Transformation background brings a fresh perspective to Defence Bank and the future growth of our business. Mirella’s strong process reengineering, change management and continuous improvement skills are invaluable as we continue to drive growth and innovation. 

Mano Simos

BBus Accounting, Grad. Dip. Banking & Finance, GAICD 

Chief Risk Officer

Mano has been Chief Risk Officer at Defence Bank since October 2013.

He is primarily responsible for the development and oversight of the Bank’s Risk & Compliance Management Framework. Mano leads a team which collaborates with executives and their teams providing guidance and advice on the implementation of these frameworks. This second line function remains independent of the business and provides the Board and the Risk & Compliance Committee with assurance and insights around the management of our current and emerging bank-wide risks including credit and climate risk oversight, 0perational risk management, resilience planning and financial crime. In addition, Mano and his team have responsibility for the implementation of the Strategic Internal Audit plan using an outsourced model, and procurement of adequate Group Insurance policy coverage.

Prior to joining Defence Bank, Mano worked at NAB - directly with the Business Banking CRO and with the Group Executive Business Banking as secretary to its Risk Committee and responsible for risk governance.

Mano is a graduate member of the AICD.