Government ministers Martin Ferguson and Kim Carr have become the latest casualties in the wake of yesterday's abortive Labor leadership spill.

Both quit over their support for Kevin Rudd, who says he did not challenge Julia Gillard because he did not have the numbers to win.

There have now been seven resignations since Ms Gillard invited the spill following calls from party elder Simon Crean, who was sacked from Cabinet.

Mr Ferguson stood down as the resources, energy and tourism minister about an hour before Senator Carr said he would quit as minister for human services.

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They joined Chris Bowen, who stepped down as tertiary education minister this morning.

Mr Ferguson said he would have voted for Mr Rudd, saying he would have given the Labor Party the change it needed.

"I was worried about where we were heading from an electoral point of view. For those reasons I would have voted for Kevin Rudd and Simon Crean," he said.

Senator Carr said he thought a leadership change yesterday was the "last opportunity" for Labor to win the election.

Kim Carr said he thought a leadership change was the last opportunity for Labor to win the election. ( AAP: Lukas Coch )

"I took the view that this week was the last opportunity we had to produce a Labor team, which in my opinion would have the strongest possible opportunity for Labor to remain in government," he said.

"That is not to say there aren't other opportunities to stay. I would never write the Labor Party off. Never.

"But I solemnly believe that Kevin provided the best opportunity and that's clearly what the evidence suggests across this country that the people would like to see.

"That is not going to happen."

Senator Carr said the numbers for Mr Rudd in the frantic counting before yesterday's spill were "very, very close".

"Don't listen to the nonsense being spoken to the contrary. The fact is that there was not a majority there. Simon Crean did a very courageous thing but no-one followed him," he said.

"Kevin had already indicated that he wanted to see and only would accept the draft on the basis there was a clear majority.

"The majority wasn't there because no-one came with Simon. I had hoped that people would support Simon's call. They did not."

Rudd thanks supporters

Sorry, this video has expired Time to 'bring people into the tent': Rudd (Photo: AAP)

Mr Rudd this morning issued a statement ruling out ever being Labor leader again.

He later told reporters in Brisbane that he did not challenge Ms Gillard yesterday because he did not have the numbers to win.

"I gathered my key friends and ministerial colleagues together in my office yesterday afternoon after Simon Crean's statement and I asked for their views," he said.

"I asked Chris Bowen for his views. I asked Anthony Albanese for his views. I asked Joel Fitzgibbon for his view, Richard Marles, Alan Griffin, as well as Kim Carr.

"And the truth is this, I asked them, what are the prospects for us obtaining a significant majority? Their collective response was zero.

"I asked them what are the prospects of us obtaining a majority, to which their response was zero.

"I then asked them under these circumstances... what should I do? Each of them said to me, 'Kevin, I believe you should not run because it would divide the party'."

Mr Rudd paid tribute to his backers who have fallen on their swords, including Joel Fitzgibbon, Richard Marles, Ed Husic and Janelle Saffin.

Spill fiasco: The casualties so far Simon Crean Elder statesman who sparked the spill. Sacked for disloyalty before Question Time on Thursday. Chris Bowen Ex-immigration minister, resigned all portfolios at an emotional press conference the day after the spill. Martin Ferguson Former ACTU boss, resigned as resources, energy and tourism minister to go to the backbench. Joel Fitzgibbon Chief whip who set the hounds running on Wednesday, says he will keep quiet for the foreseeable future. Kim Carr Minister for human services and previously demoted Rudd backer, he has quit the ministry. Richard Marles Forced to resign parliamentary secretary role after coming out strongly for Rudd on Thursday. Ed Husic Western Sydney MP who quit as whip after expressing no confidence in Gillard. Janelle Saffin Long-time Rudd backer who resigned as whip after the challenge collapsed.

He singled out Mr Bowen for praise.

"I see in him a future prime minister of Australia, he is a very good man, he has a good heart and a very strong mind and is a man of integrity," Mr Rudd said.

"His service in a number of portfolios, including the really hard ones, shows that this bloke has a future."

Mr Rudd, who repeated his intention to stand at the next election in his seat of Griffith, said it was now time to "put a line under it" when it comes to the Labor leadership.

'Courageous'

Mr Ferguson delivered a stinging assessment of some of the Government's policies, saying he considered resigning when the mining tax was changed after he promised the companies it would not be.

He said he would stand at the September 14 election and give the Government his absolute support from the backbench.

The former head of the Australian Council of Trade Unions (ACTU) urged the party to reclaim the legacy of the Hawke and Keating governments.

"Reclaim the legacy of Hawke and Keating of being a reforming government and a government that governs for all Australians," he said.

"A modern Labor Party should appeal to all Australians. The way forward for Labor is to send a very strong message that that's what we're all about.

"When you look at the way we handled the global financial crisis, Australians didn't appreciate that there was a worldwide recession. Things were going well, then we got ourselves derailed from the mining tax dispute."

He also praised Mr Crean for his "courageous" move to trigger yesterday's leadership spill.

Reflecting 'reality'

Ms Gillard said Mr Rudd's statement this morning "reflects the reality".

Speaking at a media conference in the northern New South Wales town of Bangalow shortly before Mr Ferguson's announcement, Ms Gillard again declared the leadership issue was over.

"I've seen the media reports of the statement and I think it reflects the reality," she said.

"This issue is over and done with. I was very clear about that yesterday and let me be very clear again today. This issue has been resolved for all time and I think Kevin's statement reflects that."

Ms Gillard says she will make an announcement about changes to her ministry in the coming days.

"There are a number of people clearly considering their position. And I too will consider ministerial arrangements over the next few days," she said.

"I will make some decisions about the ministry over coming days and then we will announce them when those decisions are made."

Ms Gillard also said she was tough enough to deal with the internal politics of the Labor Party.

"Look, I'm someone who's made of pretty strong stuff. That's been on display. Politics is not an easy business," she said.

"But what's always driven me throughout all of my days as a member of Federal Parliament and what drives me as Prime Minister is a vision of our country and getting that achieved."

Senior minister Bill Shorten, who supports Ms Gillard, welcomed Mr Rudd's declaration to rule out a future leadership challenge.

"The idea that Kevin Rudd is right there supporting Julia Gillard, that's good news, and it's bad news for Tony Abbott."