Senior Liberals are closing ranks around Opposition Leader Tony Abbott after accusations by Liberal MPs that he is leaving them in the dark over important policy decisions.

In the Coalition party room yesterday, Victorian MP Kelly O'Dwyer and Paul Fletcher from New South Wales questioned the economic wisdom of retaining the Government's superannuation boost while, at the same time, dumping the mining tax that funds it.

The decision was made outside the party room by the Liberal leadership group - although key finance spokesman Andrew Robb was excluded from the phone hook-up a fortnight ago.

Liberal sources have told ABC News Online Mr Abbott was "annoyed" by the party room dissent and told Ms O'Dwyer, who once worked for then Treasurer Peter Costello, to talk to her former boss about it.

"It wasn't a good look," one MP told ABC News Online, saying a number of MPs were unhappy about the way Mr Abbott reacted.

This morning, Mr Robb said reports Mr Abbott was "testy" and "angry" at the line of questioning were not accurate, although "he did suggest that he would prefer to move on to other business".

"He answered the questions about the decisions that were taken in regard to superannuation. He gave the rationale and that was it," Mr Robb told ABC NewsRadio.

He denied there was concern in the ranks about the leader making decisions without consulting the party room.

"There was a request for an explanation on decisions but, in the end, with a lot of decisions, they do reside with the leadership group.

"Tony Abbott pointed out it is always the prerogative of the party room to, in the end, have the final say if they wish on any decision."

Mr Abbott's deputy, Julie Bishop, yesterday defended him in the party room against Government accusations that his default position is to oppose all policy and that he has not suggested alternatives.

The latest Newspoll figures showed Mr Abbott's preferred prime minister rating slipping even as the Coalition increased its lead over the Government.

"The point I was making is that we are not going to be railroaded into releasing policies at Labor's bidding," Ms Bishop told Radio National.

"Let's face it, last week the Labor Government did come up with three very good policies and we supported each one of them. If they stumble upon a good policy we support it."

Ms Bishop said she didn't see Mr Abbott "take any heat" from the backbench in the party room.

"Our party room debates are always robust. I'd suggest Tony Abbott is under less pressure in his party room than Julia Gillard is in hers," she said.

Mr Abbott has had a tough couple of weeks, facing questions why he was overseas when the carbon tax, which he has made the centrepiece of his campaign to win government, was passed by the Senate.

The Government also sought to paint him as shallow and parochial for making political points in his speech of welcome to US president Barack Obama.

His opponents also claim there is a $70 billion "black hole" between what he has promised and what he can fund, given that he has promised to scrap the carbon price and the mining tax.