West Australian opposition leader Mike Nahan expects former premier Colin Barnett to retire from politics this year but believes he first wants to ensure his legacy is not trashed.
Dr Nahan has not spoken to Mr Barnett about it, but believes WA's second longest-serving post-war premier wants to see the September budget handed down.
"I expect him, in his own good time, to leave this year but it's his choice," Dr Nahan told ABC radio on Wednesday.
"He was an extremely dominant leader for a long period of time ... it was his show.
"I think he's going to wait around for the budget to see what happens. He does have a legacy that he wants to comment on, I'm sure."
Dr Nahan said he trusted the former premier, who he had known for 30 years, and said Mr Barnett had recently helped him put together the WA Liberals GST submission to the Productivity Commission.
Mr Barnett has so far remained tight-lipped about his future.
If he does exit politics, it will spark a by-election in his safe seat in coastal Cottesloe.
Dr Nahan also spoke candidly about the Liberal party's March election loss, saying he knew defeat was coming but did not know the swing would be so big, with Labor winning 41 of the 59 seats.
He said there was nothing more local members could have done and while he did not take the defeat personally, it was hard to lose so many colleagues.
The 67-year-old former treasurer said he was committed to four more years, describing himself as "the leader, not the boss".
"I'm actually quite good for this post (as opposition leader) because I'm very, very experienced in the transition to government," he said.
"I was a commentator forever, I was a former bureaucrat, so nothing that comes across our observations for comment is new to me."
