Abbott quits Libs front bench | National News | Breaking National News in Australia

SENIOR Liberal frontbencher Tony Abbott has resigned from the shadow cabinet fuelling speculation Malcolm Turnbull may soon face another leadership challenge.

Mr Abbott said after question time he and Liberals Senate leader Nick Minchin told Mr Turnbull the coalition should delaya vote on Labor's emissions trading scheme until next year.

"Malcolm was unprepared to reconsider," Mr Abbott said.

"I indicated to Malcolm at the end of the conversation that given his position I could no longer support the opposition's policy and therefore could no longer be in the shadow cabinet."

"This is a very difficult decision for me," Mr Abbott told reporters in Canberra.

"I have always regarded myself as a loyal party man, I have always been someone who instinctively supports the leader."

Liberal senators will hold a partyroom meeting at 1830 AEDT where Liberal powerbroker Nick Minchin is expected to stand down from the opposition front bench.

Liberal MP Sophie Mirabella has also announced her resignation from the opposition shadow ministry over the emissions trading scheme.

Ms Mirabella was the opposition's spokeswoman for early childhood education, childcare, status of women and youth.

She said her decision to resign wasn't easy.

"It is with a heavy heart that I will cross the floor for the first time in my parliamentary career," Ms Mirabella said in a statement on Thursday.

"This will be a vote against Labor's ETS, not my colleagues."

Mr Abbott said it was not a leadership issue, but a policy issue.

He said over the past six months he had been very active in supporting Mr Turnbull, some times in difficult circumstances.

"Thisisn't a leadership issue at all, it is policy issue, although,obviously I would much have preferred the leadership to have taken usin a different direction on this issue," he said.

Asked if he was going to challenge for the leadership, Mr Abbott replied: "I am notgoing to talk about discussions I might have had with colleagues.

"I can't say what might happen in the future but as far as I am concerned this is a policy issue not a leadership issue."

MrAbbott said his office had an "absolute deluge" of critical emails after Mr Turnbull announced the coalition's support for the amended ETS.

"The phone lines have been in meltdown with people saying that the Liberal Party would not be doing its job as an opposition simply to pass this thing without scrutiny ... it demands," he said.

Mr Abbott said it had been a "pretty heavy week" for the party.

"And for someone who has a record of loyalty to the party and to the leader that I've had, this has been an incredibly momentous decision."

Pressed on whether he supported Mr Turnbull as leader, Mr Abbott said: "I've just resigned from the front bench and obviously I do not support the policy direction that he is taking the party on this issue."

Mr Abbott would not speculate whether he and Senator Minchin had the numbers in the Senate to block the ETS legislation.

"I'm not going to speculate on what the situation might be in the Senate," he said.