I would have won election, says ousted PM Tony Abbott

Tony Abbott has launched a defensive of his prime ministership, saying he would have won the federal election with budget cuts and lower taxes.

"The poll-measured unpopularity of the Abbott government was not due to any shirking of responsibility but to our determination to do our duty by getting our own spending under control," Mr Abbott says in a forthcoming essay obtained by The Australian.

The former prime minister has also issued a warning for Malcolm Turnbull saying his successor's biggest challenge will be to retain popularity once he has a credible narrative of his own.

Mr Abbott said he wore his unpopular 2014 budget as a badge of honour and that the problem was less that it was tough but more that it failed to pass the parliament.

"Indeed, one of the strongest endorsements of the Abbott government's economic policy has been Malcolm Turnbull's pledge to maintain it," he said.

Mr Abbott was careful not to take a direct swipe at Mr Turnbull but issued a critique of senior Liberals for the "very well-organised" September 2015 spill "who didn't want the Abbott government to succeed".