This is it — there has to be no way former premier Colin Barnett can remain in the WA Parliament alongside his party colleagues after this latest spray.

His colleagues' patience was already wearing thin after enduring eight long months of him sniping from the sidelines.

They were fed-up with his continued inability to resist grabbing the spotlight by delivering very public outbursts.

Many of them believe it's stifling their attempt to move on from March's thumping election loss and stealing oxygen from the new Liberal Opposition team.

Most now agree that any patience they had left has totally evaporated after he criticised the "lack of horsepower" of his second-term cabinet during a wide-ranging newspaper interview.

"The second-term cabinet was not as strong as the first. In any cabinet, whether it be federal or state, you usually have half a dozen people who are the drivers. And I lost most of my drivers," Mr Barnett said in a magazine piece published by The West Australian on Thursday.

"I was conscious of the lack of horsepower in cabinet the second time around. It frustrated me when I had some ministers who were not dealing with what I thought were pretty simple things."

Dr Nahan wants Mr Barnett to quit politics. ( ABC News: Eliza Laschon )

Nahan unleashes frustration

As Mr Barnett's colleagues arrived at Parliament House today, it was quickly apparent his latest ill-disciplined comments had gone down like a lead balloon.

Colin Barnett's political career August 1990: Elected member for Cottesloe in a by-election

Elected member for Cottesloe in a by-election May 1992: Appointed deputy opposition leader

Appointed deputy opposition leader February 1993: Helps Richard Court defeat the three-term Labor government to return the Liberals to power

Helps Richard Court defeat the three-term Labor government to return the Liberals to power February 1993: Appointed to cabinet as minister for resources development and energy. Later adds education portfolio

Appointed to cabinet as minister for resources development and energy. Later adds education portfolio February 2001: Returns to opposition after Geoff Gallop's Labor wins election

Returns to opposition after Geoff Gallop's Labor wins election March 2001: Appointed opposition leader and opposition treasury spokesman

Appointed opposition leader and opposition treasury spokesman March 2005: Loses election and replaced by Matt Birney as opposition leader

Loses election and replaced by Matt Birney as opposition leader November 2007: Announces plan to retire from politics at 2008 state election

Announces plan to retire from politics at 2008 state election September 2008: Appointed opposition leader unopposed after Troy Buswell's resignation to defeat Alan Carpenter and become premier of WA

Appointed opposition leader unopposed after Troy Buswell's resignation to defeat Alan Carpenter and become premier of WA March 2017: Loses election to Mark McGowan's Labor by a landslide

Loses election to Mark McGowan's Labor by a landslide December 2017: Announces decision to retire from politics in early 2018

While some carefully sidestepped the issue when quizzed by waiting reporters, others claimed to not have read the interview.

But a few senior Liberals, including Opposition Leader Mike Nahan, appeared to finally be unwilling or unable to hold back any longer, and decided to bite back.

Some of those second-term cabinet members, including Liza Harvey, Terry Redman, Dean Nalder and Bill Marmion, remain his parliamentary colleagues.

Dr Nahan went so far as calling on Mr Barnett to leave politics.

"I would like to see refreshment in the seat of Cottesloe," he said.

He said most of the problems in Mr Barnett's government were created in his first term, and criticised his massive expenditure commitment as beyond what the state could afford.

Mr Nalder, who attempted an unsuccessful leadership challenge against Mr Barnett when the Liberals were still in government, said the former premier "has an inability to self-reflect."

Former Nationals leader Terry Redman also expressed his displeasure, labelling the former Premier's behaviour disappointing.

These were just the colleagues who spoke on the record to reporters.

Others who've spoken privately to the ABC are outraged to the point of letting off a stream of expletives about their former leader when asked about his latest comments.

Some colleagues and former colleagues have labelled him "nasty", "selfish" and "narcissistic" on the back of his latest media interview.

Colin Barnett has stood by his comments about his former cabinet colleagues. ( News Video )

Barnett doubles down

True to form, on his way into Parliament this morning Mr Barnett wasn't backing away from his blunt assessment of his second-term cabinet, saying he was simply being "honest."

"I say it as it is and that's my assessment," he said.

"It's no disrespect to any of the ministers in the second term, but I think we lost five very good ministers from the first term. That has an impact, it's simple as that."

Again he refused to be drawn on when he plans to leave politics.

But it's hard to see how his colleagues can continue to turn a blind eye to Mr Barnett's continued ill-disciplined behaviour.

While the Liberal Party can't force him out of Parliament, they can attempt to make his life in politics as unpleasant as possible.

Some have already privately declared that's what they plan to do.

Mr Barnett already casts a very lonely figure in Parliament, but he's just isolated himself even further through his latest commentary.

Now even some of his long-term supporters want him gone — and in their view the sooner that happens the better.