Opposition treasury spokesman Joe Hockey has revealed he has been sounded out by colleagues to take over the Liberal leadership from Malcolm Turnbull.

But he has insisted Mr Turnbull has his full backing.

Speaking on Fairfax Radio today, Mr Hockey confirmed he has been approached about taking up the top job as Mr Turnbull continues to battle poor polls and internal division.

"People talk to me about all sorts of things," Mr Hockey said."I'm not going to lie and pretend something hasn't happened.

"I don't want to disclose what I speak to my colleagues about, but I am very focused on beating Labor at the next election."

Mr Hockey says Mr Turnbull has his complete loyalty.

"He's giving it his best shot and I'm totally supporting him in that," he said.

Mr Turnbull's leadership has been destabilised in recent weeks as the internal stoush continues over how the Opposition should handle emissions trading.

Last week Mr Turnbull declared he could not lead a party that did not act on climate change and lashed out at "anonymous smart-arses" who were publicly criticising him.

Asked today by reporters if he is "looking over his shoulder" in the wake of Mr Hockey's comments, Mr Turnbull replied: "Not at all."

"I'm always looking straight ahead and I'm focused on our opponents."

Shadow cabinet is meeting this afternoon to decide on emissions trading amendments to take to the party room for approval on Sunday ahead of the resumption of Parliament.

Going into the meeting Mr Hockey was tightlipped in the wake of his earlier comments as were several of his other colleagues.

Mr Turnbull dissmissed the speculation and says he has the full support of the party.

"Yes absolutely and I have the support of the whole part yroom so we're in very good shape, don't worry about it," he said.

Mr Turnbull has maintained he is confident of getting party room backing for changes he will take to the Government despite vocal criticism from some who do not want a scheme passed this year.

Yesterday's Newspoll also saw support for the Liberal party fall to 31 per cent.