Mr Andrews, who has held the seat of Menzies since 1991, has also hit back at suggestions he should make way for newer faces, saying it is "not a matter of age" but "enthusiasm [and] ability" when it comes to prize positions in politics.

His comments, in an exclusive interview with Fairfax Media, follow speculation within the Liberal Party that Ms Credlin could leave her role as Tony Abbott's top adviser ahead of the 2016 federal election. Amid tensions between Mr Abbott's office and government MPs, it has been suggested that Ms Credlin could take Mr Andrews' safe Melbourne seat of Menzies, among other positions in the lower and upper houses.

The Victorian-born and raised Ms Credlin has previously made it known in Liberal circles that she would be keen to stand for a Victorian spot.

On Tuesday, when asked about Ms Credlin's parliamentary ambitions, a spokeswoman for the Prime Minister said: "Peta Credlin has no intention of running for Parliament at this time – state or federal, House or Senate," fuelling speculation that a parliamentary career was a live option.

On Wednesday, Mr Andrews said it was "total nonsense" and "baseless speculation" to suggest that he would leave parliament. He said his plans for welfare reform, which are slated to involve overhauling the payment system and a complex new IT infrastructure, were a "two-term project". "I'm enthusiastic to carry it through," he said.

Mr Andrews added that Ms Credlin had "made it clear" that she did not want a parliamentary position, not just to the media but to "many people in the party".

"My sense is that Peta is totally committed to the job that she's doing. She's doing a bloody good job. It's not the easiest job in the world. Especially [in a] first-year, first-term new government."

Mr Andrews, 59, believes that continued talk about his future, despite his firm plan to stay put, is being fuelled by ambitious younger MPs.

But the Social Services Minister dismissed the idea that he should stand aside from his seat in the interests of party renewal, even though earlier this month he talked of the need for "renewal" in the Victorian Liberal Party after its election loss.

Mr Andrews, who held senior ministerial positions during the Howard government, said the government needed "a combination of experience, plus newer, younger people coming through".

"It's not a matter of age," he argued. "It's a matter of enthusiasm and a matter of ability."

Mr Andrews stressed that, at a meeting of Liberal members in his electorate on Monday night, there was "warm" applause when he said he intended to stay put, adding he had the "confidence" of his local electorate council.

Speculation about Ms Credlin's potential parliamentary career has been accompanied by reports of friction between the Prime Minister's chief-of-staff and senior ministers, including Foreign Minister Julie Bishop. This follows ongoing complaints from government MPs that Ms Credlin is too controlling.

Mr Andrews issued a warning to his colleagues, urging them to stay "united [and] disciplined" as the Coalition ends its first full year in government.

"My only message to anybody who wants to hear, is to repeat what Benjamin Franklin told his fellow revolutionaries: 'If we don't all hang together, we'll all hang separately'."

When asked if he thought Liberal MPs were "hanging separately", Mr Andrews replied that "the Prime Minister said himself 'we're a bit ragged'. That's a reasonable observation."

He added that recent announcements about paid parental leave and the GP co-payment showed the government was keen to refocus on policy matters.