The woman was working for a contractor hired to administer vaccines in aged care facilities when she used three leftover doses that would otherwise have been discarded, she told 2GB on Monday.

Each family member was eligible to receive Pfizer, she said.

"I believe I did the right thing," Christine, who didn't give her last name, told the Sydney radio station.

"I mean part of the code of conduct is to be smart and cost-effective."

The federal government's excess dose policy dictates what should occur in the event of excess doses.

It states doses should be used on residents able to provide on-the-spot consent, before vaccine workforce provider staff, the facility's staff, residents' family members or carers and any other regular visitors to aged care facilities.

Her former employer, Healthcare Australia, said the woman was terminated for failing to comply with current health department protocols.

"In the event that there is still excess that cannot be used on eligible individuals as determined by the Commonwealth, HCA follow the government policy for disposal," a spokeswoman said.

NSW's chief medical officer said she wasn't in a position to know about the case, and declined to comment on whether the nurse should be reinstated.

"All I would like to stress is I do not want any wastage of Pfizer," Dr Kerry Chant told reporters on Monday.

About 460,000 shots were administered in NSW last week.

The proportion of the state's population aged over 15 with at least one dose - the group used for federal government targets - rose last week from 37 per cent to 41 per cent.

Australian Associated Press