Federal Health Minister Greg Hunt is expected to announce he will quit politics after 20 years in parliament.
Media reports suggest Mr Hunt will use the last sitting week for the year to announce on Thursday he will not recontest his Victorian seat of Flinders at the next election.
When asked about the expected retirement, Treasurer Josh Frydenberg said Mr Hunt was his closest friend in parliament.
"We are very dear friends and he has been an outstanding health minister through the crisis," he told reporters in Canberra on Wednesday.
"I will wait to see the details of Greg Hunt's comments."
Just weeks ago, Mr Hunt was quizzed about his political future on the ABC's Insiders program, and indicated he would seek another term.
He told the program he was "pre-selected and running" for the 2022 election.
Mr Hunt has held Flinders since 2001.
At the last election, he held the seat by a margin of 5.6 per cent.
The current sitting week is the last for the year, and potentially before the next election which is due to be held by May 21.
Australian Associated Press