Opposition Leader Malcolm Turnbull is unlikely to bounce back from disastrously-low approval ratings to become prime minister, Newspoll chief Martin O’Shannessy says.

The latest Newspoll, published in The Australian on Tuesday, showed Mr Turnbull’s approval rating fell by three points to 16 per cent, the same level Brendan Nelson had when he was dumped as opposition leader.

Support for Prime Minister Kevin Rudd rose two points to 66 per cent.

Mr Rudd played down his commanding lead in the polls, while opposition frontbencher Tony Abbott said Mr Turnbull should remember that former prime minister John Howard also suffered from low poll ratings.

Mr Turnbull’s rating is now worse than Mr Howard’s lowest during his unsuccessful first term in opposition.

Mr Howard’s poll rating of 18 per cent in December 1988 inspired a front-page headline in the now defunct Bulletin magazine: “Why does this man bother?”

Within five months, the Liberal Party dumped Mr Howard as leader in favour of Andrew Peacock. The coalition spent another seven years in opposition.

Asked if Mr Turnbull had a hope of becoming prime minister, Mr O’Shannessy said the scenario was unlikely.

“John Howard got pretty close to these sort of numbers in his first round as opposition leader but we’ve never seen a situation where an opposition leader has been able to come back from so low,” he told Sky News on Tuesday.

“We’ve seen three consecutive polls where Mr Turnbull hasn’t been able to regain any traction.”

Mr Turnbull’s call for Mr Rudd to resign over the acceptance of a free ute from his Brisbane neighbour had backfired, Mr O’Shannessy said.

“It ended his fightback that he had been doing since the beginning of the year,” he said.

Mr Rudd downplayed the Newspoll results, saying the government was focused on delivering Labor’s election commitments.

“These things go up, they go down,” he told the Nine Network on Tuesday.

“The important thing is to just keep your eyes focused on the main game.”

Mr Abbott pointed out that Mr Howard and 1990s Victorian premier Jeff Kennett had also suffered from poor polling in opposition.

“There are lots of great leaders, very successful leaders, who went through pretty dire patches in the polls,” he told ABC Radio on Tuesday.

On a two-party preferred basis, Labor has a 57 per cent to 43 per cent lead over the coalition.

Opposition health spokesman Peter Dutton says Mr Turnbull is doing a good job.

“It’s a tough job,” he told Sky News on Tuesday.