Suddenly it is Scott Morrison that faces a potential major reshuffle of his ministers, rather than Labor considering changes at the top.
The resignation of Mathias Cormann has been rumoured for some time, but his plan to leave politics at the end of the year leaves a major hole in the prime minister's cabinet.
Senator Cormann as finance minister has been a bedrock for the coalition since it came to power in 2013.
While he is staying on for the much-awaited economic statement on July 23 and the budget in October - which was delayed because of the coronavirus pandemic - he has been crucial in negotiating legislation through a sometimes hostile Senate.
Senator Cormann will stay as finance minister until the end of the year at which time Mr Morrison can put together the final touches to his team in the parliamentary summer break.
Rumours suggest Trade Minister Simon Birmingham will fill the vacant finance minister role, as has Home Affairs Minister Peter Dutton.
But Mr Dutton has also been linked to a move to the defence portfolio, all of which assume he wants to leave his powerful and broad Home Affairs department.
Immigration Minister David Coleman has also been away for months for personal reasons, raising speculation as to whether that position will also be up for grabs. Cities and Urban Infrastructure Minister Alan Tudge has been acting in the role in his absence.
Meanwhile, Anthony Albanese's position as Labor leader looks safe for now after the party appeared to have just held on to the NSW bellwether seat of Eden-Monaro following this weekend's by-election.
There had been talk his leadership would be under attack from within should Labor candidate Kristy McBain have lost.
"Full credit to Anthony Albanese who injected himself energetically into this campaign, and looks like he's walking away victorious," Labor's agriculture spokesman Joel Fitzgibbon told ABC's Insiders program.
Asked if Mr Albanese is now guaranteed to lead Labor into the next election. Mr Fitzgibbon said: "Absolutely".
Australian Associated Press