The Member for Eden-Monaro Mike Kelly told Fairfax Media on Thursday that he voted for Kevin Rudd, but the decision was emotional and taken with a "heavy heart".
"Kevin is a magnificent campaigner, he has tremendous capacity, he almost single handedly steered us through the global financial crisis," he said.
"He brings to the job great communication skills, great campaign skills."
Dr Kelly said he did see the so-called "phantom petition" which was circulating on Wednesday, calling for a special caucus meeting.
He said the leadership change was distressing because he had the utmost respect and affection for both Julia Gillard and Mr Rudd.
"Labor's legacy must be defended and the best way to do that, in my opinion required the change," he said.
"My community has certainly let me know in no uncertain terms that that was what they wanted.
"They have also been absolutely clear they detest Tony Abbott.
"They wanted an alternative to that and Kevin Rudd was the alternative they wanted.
"Kevin Rudd now puts us in a position to transform the campaign into a proper policy debate.
Dr Kelly said he believed he now had a better chance of holding the bell-weather seat, centred on Queanbeyan.
"People have been very happy with the work that I've done but they also made it very clear to me that they did want to see a return to Kevin Rudd," he said.
"So, given that the community now has what they wanted in that respect, I think that does strengthen my chances.
"Importantly it means my opponent [Liberal candidate Peter Hendy] has got to stop hiding behind this simplistic line that if you vote for Mike Kelly you're voting for Julia Gillard.
"Now he has to come forward with some real policy."
Dr Kelly said he was delighted to serve in the Defence Materiel portfolio if Mr Rudd wanted him to continue.
He is planning to produce a defence industry policy statement within weeks.
Meanwhile, member for Canberra Ms Gai Brodtmann said on Thursday the electorate had turned off politicians.
"They didn’t like Tony Abbott and they weren’t listening to Julia Gillard," she said.
The member for Fraser, Andrew Leigh, who has been parliamentary secretary to former prime minister Julia Gillard, told Fairfax Media on Wednesday that he continued to support her.
He said on Thursday the majority view in caucus was that Mr Rudd could do a better job in the next election.
"I very much hope that is the right view," said Dr Leigh.
"I respect that and I will be backing Kevin Rudd every day until polling day."
Dr Leigh said he was prepared to resign his position as parliamentary secretary.
"It's really whatever is most useful for Kevin and the new leadership team," he said.