Leadership team

The Executive Leadership Team lead the staff of Merri Health to achieve common goals that are in line with Merri Health’s vision and purpose.

Members of this team include our Chief Executive Officer, Chief Financial Officer and four General Managers.

Tassia Michaleas

Chief Executive Officer

BEC, BSW, MBA, AFCHSM, GAICD

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Tassia has extensive experience in the not-for profit and community sector and commenced her career in community health in 1996. Tassia has experience working across leaderships and operational areas and takes a pro-active approach in developing and delivering innovative services and programs, to identified and emerging community needs. Tassia has strong skills in advocacy, streamlining of systems and processes, effective engagement of stakeholders and developing partnerships. Tassia is committed to and has an in-depth understanding of the values and philosophy of community health, including issues related to access, diversity and the social model of health. 

Tassia holds Bachelor of Economics, a Bachelor of Social Work and a Master of Business Administration. She is an Associate Fellow of the Australian College of Health Service Management and a Graduate of the Australian Institute of Company Directors.


Dr. Antoinette Mertins

General Manager, Aged and Primary Care

DrPH, PDipHRM, BBSc, GAICD, AFCHSE

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Antoinette has extensive experience working in the public and not-for-profit sector across a diverse range of organisational forms.  Antoinette has strong skills in driving workforce reform, development of innovative community based models of care and developing partnerships across aged care, health and primary care sectors.

Antoinette is a public health practitioner with an extensive background in community based health care leadership and management, service planning and development, and leading diverse multidisciplinary teams to deliver innovative services.  Antoinette is committed to population health approaches as a means to improve health and wellbeing outcomes.

Antoinette holds a Doctor of Public Health degree, a Post Graduate Diploma in Health Research Methodology and a Bachelor of Behavioural Sciences (Psychology).  She is an Associate Fellow of the Australian College of Health Service Management.  Antoinette is a recent Graduate and member of the Australian Institute of Company Directors.


Maryanne Tadic

General Manager, Healthy Communities

MPH, BHSc, AFCHSM, MAICD

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Maryanne has over 15 years of experience working in the community health sector within both leadership and operational contexts, and has a strong understanding of the diverse range of service delivery areas as well as reform challenges within the community health environment.

Maryanne has a background in population health and has experience in leading a number of community-based research projects, with extensive skills in strategic planning and evaluation.

Maryanne is passionate about driving change through innovation, and applying a systems thinking approach to achieve health and wellbeing outcomes in communities. Maryanne holds a Master of Public Health degree (Health Services Management) and a Bachelor of Health Sciences (Health Promotion). She is an Associate Fellow of the Australian College of Health Service Management and a member of the Australian Institute of Company Directors.


Gavin Thompson

Chief Financial Officer

B.Bus (Acc), GAICD, CPA

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Gavin has held a range of senior finance positions across not for profit, corporate and international sectors. He has worked in financial management in the homelessness and community service sector as well as roles in a variety of industries such as Aerospace, Investment Banking, Software Development, Retail Banking, Hotels and Trustee services.

Gavin has skills in providing strong financial stewardship to organisations while maintaining a co-operative and helpful approach to aid service delivery programs.

Gavin holds a Bachelor of Business, is a Graduate of the Australian Institute of Company Directors and is a Certified Practising Accountant (CPA).


Nessá Pastoors

General Manager, People and Communications

BCCJ, MER, EMBA

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Nessá Pastoors has worked in the non-for-profit sector for 16 years and brings a wealth of knowledge with 14 years of leadership and management experience in employment relations, project management and governance. With a proven track record of building workforce capacity and contributing to organisational growth, Nessá has been instrumental in driving organisational capacity and cultural change across various roles in the non-for-profit sector.

Nessá’s strengths lie in industrial relations, change management, stakeholder engagement and communications and marketing, with past experience as HR Manager for leading community and health care organisations. Nessá has served on local community boards.

Nessá holds a Bachelor of Criminology and Criminal Justice, Masters of Employment Relations, Certificate in Business and Human Resources Management, and an Executive Masters of Business Administration. Nessá is a certified member of the Australian Human Resources Institute and is an Accredited Lean Yellow Belt through the Australian Healthcare and Hospitals Association.


Phillip Harris

General Manager, Infrastructure

MBA, GAICD

Phil web

Phill has held senior executive roles within the information technology and infrastructure management portfolios spanning a number of industries including education, government, telecommunications and media, most recently within the health sector.

Phill’s experience includes strategic planning, business process improvement, project management, procurement and facilities management.

Phill has a Master of Business Administration, is a Graduate of the Australian Institute of Company Directors and has a Graduate Certificate in Leadership in Education and Training, as well as ITIL Service Management and Prince2 Project Management qualifications.