Tony Abbott's divisive former chief of staff has declared her support for Malcolm Turnbull but praised Bill Shorten and questioned government policy on superannuation in her first television interview.

Peta Credlin, who worked as Mr Abbott's top adviser in both opposition and government, began an  interview on Sky News on Saturday by admitting "I'm out of my comfort zone."

Despite working in Parliament House for 16 years it was the first time she had set foot in the media wing known as the Press Gallery.

"I have a reputation for straight-talking and candour": Peta Credlin. Photo: Alex Ellinghausen

Ms Credlin, widely criticised during her time at the top for being too controlling, was largely unapologetic but said she was not perfect.

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"I have a reputation for straight-talking and candour," she said. "If I have to cop some criticism, maybe I banged a few heads too hard."

She dismissed as "rubbish" that she was a hugely powerful figure in the government who Mr Abbott couldn't do without, saying he was always the boss: "The chief of staff sits in the pecking order wherever the prime minister wants them to sit."

Peta Credlin with Tony Abbott in 2012. Photo: Alex Ellinghausen

She also denied she had a frosty relationship with Foreign Affairs Minister Julie Bishop - describing their relationship as "warm" - and said she found some of the personal criticism levelled at her over the years "tough" to deal with.

Ms Credlin has taken a break from politics since Mr Turnbull toppled Mr Abbott in September, catching up on sleep, reading books and taking her mother on a European holiday. She is returning to the public eye to be a Sky News commentator throughout the campaign.

She says she was offered another political job by a "senior Liberal" in December but declined. She says she intends to enter the commercial sector after the election.

She says it was obvious Mr Turnbull stayed in Parliament after he lost the Liberal leadership in 2009 in order to retake it.

"I don't think Malcolm Turnbull stayed around after he lost the leadership ... to be anyone's minister," she said. "He has my support as a Liberal but I am frank and I am honest and I'll call it how I see it."

She says Mr Turnbull should embrace Mr Abbott's record - particularly on border security and national security - during the campaign.

She praised Mr Turnbull's first budget but questioned the wisdom of some elements of his superannuation tax concession changes.

"The issue isn't the changes proposed, I think it's the retrospectivity that might cause them some grief," she said.

Ms Credlin believes Mr Turnbull will win the election but cautions that in such a long campaign anything can happen and Labor should not be underestimated.

"We saw what happened in 2010 when everyone underestimated Tony Abbott and a really disciplined campaign can win you government," she said.

Opposition Leader Bill Shorten had brought unity and discipline to his team and had an "outstanding office".

"He has a likeability, an earthiness, a genuineness that if he was able to work that into his public presentation he would be formidable."