Our Executive team

Giles Nunis | Chief Executive

Giles Nunis has a wealth of experience and a deep understanding of the health and technology sectors, which he demonstrated on the HSS Board.

Over his career, Giles has served in various senior leadership roles in across government and industry. Prior to joining HSS, he was Executive General Manager, Digital Transformation at the WA Primary Health Alliance, where he led major initiatives to modernise and streamline healthcare delivery. 

Known for his strategic vision and commitment to digital transformation, Giles has a proven track record of delivering impactful change across complex systems.  

“I look forward to helping shape one of the most significant digital health transformation journeys in Western Australia—one that empowers health service professionals and ultimately benefits all Western Australians.” 

Karissa Fyfe | Director, Office of the Chief Executive

Karissa Fyfe brings a wealth of experience in policy, governance and reform. Throughout her career, she has driven major initiatives aligned with government priorities, working collaboratively across agencies and stakeholders to deliver practical outcomes.

With expertise in program delivery and organisational reform, Karissa has provided trusted advice to senior executives and ministers, strengthening decision-making and reporting capabilities.

As Director, Office of the Chief Executive, she champions strategic decision-making, governance, integrity and organisational performance, helping to deliver key priorities and support positive outcomes across HSS.

Anthony Lenzarini | Chief Information Officer

With more than 30 years’ experience in the digital and ICT sector, Anthony (Tony) Lenzarini has dedicated much of his career to WA public health, leading large multidisciplinary teams across a broad range of ICT functions and strategic digital initiatives.

A passionate technology leader, Tony is recognised for his steady solution-focussed approach and a genuine commitment to people. He continues to drive the modernisation of HSS’s digital services, with a strong focus on delivering simpler, faster, and cost-effective outcomes for WA Health. His leadership in cyber security and connected healthcare collaboration is critical to protecting and enabling our services in the future. 

Chad Martino | Acting Executive Director, Transformation and Strategy

Chad has worked in the WA public sector for the past several years, including six years in a senior executive role at the Department of Health. 

Chad brings a wealth of knowledge and experience across diverse portfolios, in particular Government and stakeholder relations.

An experienced health leader, Chad specialises in issues and crisis management, corporate strategy, stakeholder engagement, policy implementation, government relations, change management and strategic leadership.

“HSS has an ambitious reform agenda that will make a positive difference across our broad health system. I am looking forward to working with the leadership team to continue to drive improvement and build on our success to date.”

Amanda Mulcahy | Acting Executive Director, System-wide Workforce Services

Amanda Mulcahy is a senior health executive with extensive experience spanning workforce strategy, health policy, performance reporting, governance and organisational leadership. 

She brings a strong focus on system performance and optimising our health workforce. She is passionate about using data and insights to drive actionable health system change. Amanda is committed to ensuring these efforts translate into better outcomes for patients, families and communities.

Neha Patel | Executive Director, Human Resource Management Information System

Neha Patel is a visionary technology and business leader with over 15 years of experience delivering high impact programs across telecommunications, Cloud and enterprise technology with proven success leading large scale portfolios, including Delivery Performance across Telstra’s $400m+ portfolio. 

She has held senior leadership roles in the private sector and through those roles has served the public sector, shaping digital, infrastructure and transformational strategies.  

With a deep understanding of service delivery and the operational realities of large-scale environments, Neha is known for her strategic acumen and dedication to fostering inclusive leadership.  She is passionate about working with purpose and driving meaningful community impact and serves on the boards of multiple not-for-profit organisations. 

Neha is leading the delivery of HRplus, a HR, payroll and rostering solution for the WA health system, with rollout commencing in 2025. 

Emily Pestell | Executive Director, People, Capability and Culture

Emily Pestell has broad business experience in leading governance, strategy and organisational transformation. She began her career at the Department of Finance before joining WA Health in 2014.

Emily established the Office of the Chief Executive as a standalone business unit bringing together Governance, Risk and Compliance, Internal Audit, Communications, and Ministerial and Parliamentary Liaison. In 2020, she played a key role in HSS' COVID-19 response and successfully led the establishment and implementation of the inaugural HSS Board.

Throughout her career at HSS, Emily has led significant transformation initiatives across governance, customer experience, compliance and people-related functions. She was instrumental in preparing HSS for the adoption of a new HR and rostering solution in 2025.

As Executive Director, People, Capability and Culture, she continues to drive strategic priorities and strengthen our culture.

Dr Sumit Sinha-Roy | Executive Director Electronic Medical Records

Dr Sumit Sinha-Roy brings extensive experience in digital health, clinical operations, strategy, and leadership. 

He played a key role in WA Health’s COVID-19 response as Operations Executive Lead and was Medical Advisor for the State Health Operations Centre for two years, where he helped advance the State Health Operation Centre's data initiatives.

With a background in acute medicine, Dr Sinha-Roy has been working with the Community Virtual Care team and Home Hospital, located in Royal Perth Hospital, focusing on remote patient monitoring initiatives. 

Mark Thompson | Chief Procurement Officer

Mark Thompson leads the modernisation of procurement and supply services to reduce supply risk, improving service delivery and maximising return on investment across HSS and the WA health system.

Mark has more than 20 years’ experience at a senior management level in the health care, utilities and telecommunications industries in the government, private and not-for-profit sectors. He led numerous multi-disciplinary teams covering procurement, contract management, purchasing, supply chain, fleet, sales and bidding.

Prior to joining HSS, Mark managed a large procurement, warehousing and logistics function, and led one of WA’s largest and most complex fleets. He implemented a major procurement operating model, which included the development of a long-term sustainable supply chain strategy.

“Working together to improve our supply chain will lead to efficiencies and increase the reliability and responsiveness of supply to support the WA health system.”

Sash Tomson | Chief Financial Officer

Sash Tomson is a management and finance professional with over 20 years’ experience as a senior executive, having held executive finance positions in private and government sectors.

Sash has extensive experience in financial management, corporate strategy and policy, evaluating the financial impact of new business initiatives, financial modelling, negotiating and overseeing commercial contracts. As well as health, he has worked in private practice, construction and mining.

During his time with WA Health, Sash served as Acting Chief Executive of PathWest and Acting Assistant Director-General at the Department of Health, demonstrating strong leadership across one of the State's most complex health entities.