Barnaby Joyce says Prime Minister Malcolm Turnbull should consider relinquishing the Liberal leadership if he doesn't lift the Coalition's poll numbers by Christmas.

Mr Turnbull hit the benchmark he used to roll Tony Abbott as Prime Minister, losing 30 consecutive Newspolls.

The poll figures, published in The Australian newspaper, showed the Coalition trailing Labor 48 per cent to 52 per cent on a two-party preferred basis.

The Prime Minister brushed off the poll result, declaring he would win the next federal election, and arguing recent Newspolls ahead of the South Australian and Tasmanian election had been unreliable.

But his former deputy had a more pessimistic assessment.

"If you truly believe this is exactly the sentiment of the people, then you also have an obligation not to drive your party, or the government, off a cliff," Mr Joyce told Sky News.

"Towards the end (of the year) near Christmas you'd have to start asking those around you what do they believe is the proper course of action from that point forward."

"Malcolm's not a fool, he knows this himself."

Mr Joyce stressed that the Coalition was a "long, long way" from a leadership change right now — and maintained he wanted Mr Turnbull to succeed.

But he said MPs would not want to go to an election if they were convinced their cause was doomed.

"Nobody wants to go to a federal election that you know you're going to lose, it's like playing in a losing side," he said.

"If they're going to lose their jobs and you're going to lose government — then, later on, you've got to do the right thing and say: 'Look, I think we have to look at a different way of doing business.'"

Coalition not setting 'artificial deadlines': Tudge

Mr Joyce's intervention has clearly exasperated federal government frontbenchers.

Citizenship Minister Alan Tudge gave a blunt response when asked about it on Q&A.

"I don't think it was a very useful contribution from Barnaby Joyce," he said.

Mr Tudge insisted Mr Turnbull's leadership was safe and said the Coalition was not setting "artificial deadlines".

Sorry, this video has expired In September 2015, Malcolm Turnbull used 30 lost Newspolls to justify a move against Tony Abbott

"Politics these days turns very, very quickly … I'm very confident as we get closer to the election the Australian people will start to focus very much on the alternative, and the alternative is $200 billion of taxes," he said.

Meanwhile, Mr Abbott is continuing to harry Mr Turnbull by publicly demanding the Government embrace a more conservative position on a raft of issues, from immigration to energy.

"What I've been saying for a long time now is that we need to give our people something to fight for, and the general public something to hope for," Mr Abbott told Sky News.

"I think that's the test. It's not the opinion polls — it's are people enthusiastic about this Government? That's the test, and I hope we can pass that test."

Dutton, Frydenberg, Morrison admit leadership ambitions

Mr Joyce's inflammatory remarks also gave a new lease of life to internal rumblings about Mr Turnbull's leadership.

Most Coalition frontbenchers and backbenchers continue to publicly back Mr Turnbull, and insist his position as leader is safe.

But behind closed doors there is deep-rooted pessimism about the Government's standing with voters — and widespread uncertainty about Mr Turnbull's future.

Sorry, this video has expired Tony Abbott says he never obsessed over polls, on the day of Malcolm Turnbull's 30th Newspoll loss

The uncertainty is feeding into broader sense of fatalism and paralysis, even though there is no immediate prospect of a challenge against Mr Turnbull.

On Monday, several frontbenchers — including Peter Dutton, Josh Frydenberg and Scott Morrison — all admitted they had ambitions to be prime minister in the future, while declaring they remained loyal to Mr Turnbull.

Mr Turnbull also said he regretted making the comments about Newspoll when he announced his coup against Mr Abbott in 2015.

At the time, he declared that the people of Australia had "made up their mind about Mr Abbott's leadership."

"I regret making those remarks at the time, making remarks about 30 Newspolls at the time," he said on Monday.

"But what I promised to do was to provide economic leadership and traditional cabinet government, and I've done both."