Under-fire Speaker Bronwyn Bishop did not even check her expenses before she signed off on the six-monthly Finance Department report which revealed the notorious $5227 helicopter charter flight.

Instead, the embattled Mrs Bishop left it to her staff to check the details before it was published on the Finance department's website.

Mrs Bishop's failure to check her own expenses occurred despite the form asking MPs to "please check the information detailed" as part of the regular reporting process and stating MPs must "certify that my use of each entitlement ... administered by Finance, was in accordance with the provisions legislated for each respective entitlement".

A spokesman for Mrs Bishop confirmed she had not checked the expense report and said "our office staff reconcile the report against the Speaker's own diary to ensure the accuracy of the certification. Once we have done that we provide assurances to the Speaker that the report is correct and she signs the certification".

Mrs Bishop maintained on Sunday the helicopter flight "was done within the entitlement. When I saw that figure, I saw it was too large and that's why I'm repaying it".

But current and former MPs including Treasurer Joe Hockey, Environment Minister Greg Hunt, former treasurer Peter Costello, former leader John Hewson and former Victorian Premier Jeff Kennett all publicly criticised Mrs Bishop's use of expenses on Sunday, though Prime Minister Tony Abbott was standing by his hand-picked Speaker

Privately, anger within Liberal Party ranks was on the rise, with ministers and backbench MPs – none of whom wished to be named – conceding Mrs Bishop may have to quit to limit the damage to Mr Abbott and the government.

One MP spoke for the more than a dozen contacted by Fairfax Media when he said that "the PM needs to tap her on the shoulder, but I don't think he will. So she needs to resign, because we should be talking about Bill Shorten, not this".

A defiant Mrs Bishop made it clear on Sunday she does not intend to resign, or apologise, despite agreeing to repay cost of the charter flight, plus a $1300 penalty.

She also defended a recent two-week trip to Europe that cost taxpayers close to $90,000, declaring: "It wasn't $90,000, it was 88 [thousand]. Indeed the President of the Senate who led the delegation to exactly the same meeting, the 12 months before, spent $92,000. So it is simply the way that delegations are arranged."

"When we talked about the helicopter, that is now with the Department of Finance, so I don't think it's appropriate to talk about it any further," she said and insisted "the best form of apology is to repay the money".

However, Mr Hockey said the scandal was sucking the oxygen from political debate and that "I haven't heard of anyone who has taken a helicopter to a fundraising event".

"She recognised that what she did was an error of judgment, paid the money and is co-operating with the Department of Finance, and that's all happened since I had that interview with 2UE," he told the Ten Network, referring to earlier criticism that the flight didn't pass the "sniff test".

Dr Hewson said the prime minister was "defending the indefensible" and warned that would come at "enormous political cost" to the government.

Mr Hunt urged an apology from the Speaker, Mr Kennett said the flight was "excessive" but that Mrs Bishop should not resign, while Mr Costello said the rules around expenses needed to be tightened because "the rule can't be that you can just turn up somewhere and talk about Parliament because then it's justified".

And Mr Shorten demanded the under-fire Speaker stand aside on Sunday, declaring the scandal had now become a test of Mr Abbott's character and leadership.

"Does Mr Abbott have the character to tell Bronwyn Bishop to stand aside? Because he knows - and the world knows - that this arrogant misuse of taxpayer funds needs to be held to account," he said.

The Speaker's decision to sign off on her expenses without checking them surprised colleagues, who pointed out that when she had been shadow special minister of state, Mrs Bishop had been meticulous about ensuring the expenses she and other MPs incurred were within the rules.

"Some MPs simply can't be bothered and leave the administration to their staff," one MP said, "but as SMOS [Special Minister of State] or shadow SMOS, you'd check it."

Labor waste watch spokesman Pat Conroy said it was "simply astounding that one of the most senior members of parliament is signing whatever is put in front of her. What else has she signed without knowing what's in it?"

Mrs Bishop would not provide the details of Liberal fundraising events attached to her taxpayer-funded flights to Young and Nowra because it would be "improper to comment" while the Finance Department investigated, her spokesman said.

A change.org petition started on Sunday calling for Mrs Bishop to be removed as Speaker had gathered more than 10,000 signatures within hours on Sunday.

with Rick Feneley, Gareth Hutchens, James Robertson

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