Twelve months after Malcolm Turnbull toppled Tony Abbott as leader of the land, former chief of staff Peta Credlin has launched a ferocious defence of her ex-boss' record.

Arguing Abbott-era policies should be credited for Mr Turnbull scraping home on July 2, she claimed there was "no doubt" Mr Abbott would have won the election with a bigger majority.

"There is no doubt in my mind that he would have campaigned with every breath in his body, and he would be in a position now as prime minister with more than one seat up his sleeve. There is absolutely no doubt," Ms Credlin told Sky News.

"I don't want to hear from bed-wetters on that score, because I was there in 2010 when everyone wrote us off, and I was there in 2013 when the landslide was delivered."