Labor is set to go to an election with gaping holes in the potential line-up for its next cabinet after Defence Minister John Faulkner announced he would go to the back bench.
The loss of Senator Faulkner from the front bench is a major blow to Prime Minister Julia Gillard after Finance Minister Lindsay Tanner announced two weeks ago he would not be contesting the next election.
Opposition Leader Tony Abbott seized on the development, saying it was a vote of no-confidence in Ms Gillard's government.
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"The two best ministers in the government are leaving it, and we now have a government with a lame duck finance minister and a lame duck defence minister," Mr Abbott said.
"These positions are too important, particularly with our troops committed overseas, particularly with the kind of international economic uncertainty that we have now, for the prime minister not to be able to tell us who will be the defence minister and who will be the finance minister after the election."
Faulkner to remain active
Senator Faulkner said the timing meant he would fulfil his commitment to former prime minister Kevin Rudd and Ms Gillard to serve as a minister for Labor's full term.
The 56-year-old, who has served as a minister in two Labor governments, said he would remain active on the back bench after being persuaded by Ms Gillard not to quit politics entirely.
Senator Faulkner revealed he was with Ms Gillard and Mr Rudd in the prime minister's office the night before the Labor leadership spill.
"There were three people involved in that meeting. Kevin, Julia and myself," he said.
But he rejected suggestions his decision to move to the back bench was due to the party's decision to oust Mr Rudd.
"I cannot say strongly enough that any such speculation is just plain wrong," he said.
"Julia Gillard has my absolute support."
PM asked Faulkner to stay
The prime minister confirmed she made a personal appeal to Senator Faulkner, asking him to stay on in politics.
"John Faulkner will be missed at ministerial level," Ms Gillard said.
"He is a senior and very, very capable figure. But he has made it clear that personally for him, that he feels that this is the right time to move from a ministerial career."
The development came as the coalition tried to shift the political focus back on to the government's troubled school stimulus building program and Ms Gillard's role in overseeing the scheme.
Mr Abbott has signalled a renewed push to tie the prime minister and former education minister directly to "waste and mismanagement" associated with the $16.2 billion program.
The opposition leader said the program was an example of the incompetence which had been a hallmark of the Rudd/Gillard government.
"They think that they can get around that by scapegoating the former prime minister, but as the Building the Education Revolution program shows, the current prime minister has been right at the heart of the waste and mismanagement under this government," Mr Abbott said.
The comments came as Mr Abbott visited Annangrove Public School in Sydney to announce a coalition government would hand responsibility for all funds not spent under the program to school principals and local communities.
The tactical shift comes after a string of positive polls for Labor since Ms Gillard replaced Mr Rudd and after a breakthrough in negotiations with the mining sector effectively neutralised the coalition's attack on a proposed mining tax.
Ms Gillard has also been able to set the agenda on asylum seekers - traditionally a coalition strong point - by announcing she will seek greater regional cooperation on the problem, including the possibility of establishing a refugee processing centre in East Timor.
