The secretary of NSW health is quitting after six years in the job.

Health minister Brad Hazzard announced on Monday that Elizabeth Koff has given notice she will resign effective from March 4.

It marks the end of a 30-year career with the NSW health system and comes after Ms Koff gave evidence before a NSW parliamentary committee commission into the government’s handling of Covid-19 on Friday.

During her appearance Ms Koff told the committee she had “no specific knowledge” of the aged care sector’s concerns about the risks of lifting restrictions once Omicron began appearing in the community.

Mr Hazzard thanked Ms Koff for her contribution over the years and for leading a workforce of 170,000 through the pandemic.

“Her distinguished leadership as Secretary of NSW Health has seen an extensive expansion and development of clinical services, a substantially increased workforce and an extensive renewal of health infrastructure across the state,” he said in a statement.

“Ms Koff has delivered key strategic programs including a focus on value-based healthcare, improving the patient experience and the digitisation of healthcare delivery.”

Mr Hazzard said her leadership through the COVID-19 pandemic had seen a rapid expansion of those systems, as well as specific responses to the pandemic, including testing clinics, vaccination clinics, hospital operations and the structures for guidance and support from clinical expert advisory groups.

“She has led and supported the most outstanding executive health team and broader health teams at times of great pressure and the NSW government thanks her for that leadership and for ensuring that NSW residents have the strongest and most capable health system in the nation,” he said.

Ms Koff has worked closely during the pandemic with a range of senior Government ministers and other senior public servants and her contribution has been extremely highly valued.