Mr Turnbull told a private gathering of Liberal Party members, including two Cabinet ministers, that the Morrison government’s climate change policy was not “coherent” and urged the party’s moderate faction “to stand up for our values and get the ­outcomes, deliver the government and the policies Australians deserve”.

The Daily Telegraph reports Mr Turnbull told the 250-strong audience that Australia must not follow the path of authoritarian populism.

Mr Turnbull made the comments during a 20-minute speech on Thursday night at a Liberal forum at the Rushcutters Bay yacht club in Sydney which doubled as his farewell.

Former Turnbull minister Christopher Pyne introduced Mr Turnbull and moderate faction leader Trent Zimmerman was the event’s MC. Two cabinet ministers attended, Simon Birmingham and Paul Fletcher, along with outgoing cabinet minister Arthur Sinodinos, who is replacing Joe Hockey as US ambassador, and Mr Turnbull’s Liberal successor in Wentworth, Dave Sharma. State Liberals in attendance included Rob Stokes, Gareth Ward and ­Gabrielle Upton.

The speech, and reference to the “quiet Australians” who Mr Morrison credits for his surprise election victory, has been interpreted by Liberals as a swipe at the PM. Following his ousting in August last year Mr Turnbull pledged not to be driven by hate and become a “miserable ghost”.

In his speech, Mr Turnbull said: “What we have got at the moment with this single issue [of climate change] which is a fundamental ­existential one ... we have got ourselves into a situation where our party is not able to present a coherent view, much to the shock of the ­business community, the ­energy sector.

“Billions of dollars of investment are being held back as a result, the government is actually creating uncertainty in the investment market and it is because people are taking something which should be a question of fact and science and physics and engineering, as I used to say, engineering and economics, and turning it into a question of ideology.

“So the real challenge for the moderates for all of us, for the Liberals in the Liberal Party is the one thing we ­cannot be, now or ever, is quiet Australians.

“We have to be loud Australians and stand up for our values and get the outcomes, deliver the government and the policies Australians deserve.”

In his speech, Mr Turnbull also spoke of how he got a lot done in a short time as prime minister, ­including same-sex marriage, national security legislation and the Trans-Pacific Partnership trade deal.

Mr Turnbull, who lives at Point Piper nearby the harbourside venue, arrived by water taxi, The Tele reports.