Party activists say that errant Labour MPs should be punished
Labour activists are calling for any MP bringing the party into disrepute over expenses to automatically face re-selection by their constituency party.
Nearly 100 supporters have signed a letter to Labour's ruling body, the National Executive Committee, calling for tougher action over the scandal.
Two MPs have been suspended from the parliamentary party over expenses.
The BBC understands Gordon Brown has said the Commons must consider giving up control over regulation of expenses.
His comments came after unprecedented scenes in the Commons in which Speaker Michael Martin faced calls for a parliamentary debate on his future amid calls for him to stand down.
According to the BBC's Political Editor Nick Robinson, Mr Brown has told a meeting of the parliamentary Labour Party that he "favours moving from self-regulation to statutory regulation" of MPs expenses by an external body - requiring new laws.
He has also suggested there should be a limit on the amount MPs could claim back for their mortgage payments.
Labour MPs Elliot Morley and David Chaytor have been suspended pending an investigation of their claims by the Parliamentary Standards Commissioner.
Both admitted to making claims for interest on their mortgage payments even after their loans had been paid off.
An inquiry is to be launched into claims a third Labour MP, Ben Chapman, was given permission to claim allowances for mortgage interest he no longer paid.
The Daily Telegraph, which has published a string of allegations about MPs' expenses, said Mr Chapman benefited by £15,000 over 10 months from the arrangement, which documents suggested was not unique to him.
Mr Chapman has said he did not believe he did anything wrong.
Ahead of a meeting of Labour's National Executive Committee on Tuesday, there are calls for the body to introduce a fast-track disciplinary process for MPs who have abused the system.
Activists say that MPs who have brought the party into disrepute should immediately have the whip withdrawn and face re-selection by their constituency parties.
They are also calling for expense claims made by Labour MPs, believed to be excessive or inappropriate, to be reviewed even if they were approved by the Commons authorities.
MPs from all parties have agreed to pay back money which they claimed under the old, now discredited, rules relating to second homes allowances.
Addressing Labour MPs on Monday evening, Mr Brown is understood to have said that all MPs who have made inappropriate claims should return the money and that the public must be involved in plans to reform Parliament.
Mr Chapman was the focus of the latest revelations about MPs' expenses published on Monday.
When asked if it was true that he had admitted continuing to claim for interest payments on his entire mortgage after repaying £295,000, he told the BBC: "It may be. I don't know."
When it was put to him that he may have been claiming more than he was paying, the MP said: "If I've done so it was following the advice the Fees Office gave me. I'll have to discuss it with them and see how it should be tackled".
According to the Telegraph, correspondence showed the MP sought and was given permission to reclaim the interest payments on the full value of his original mortgage, despite paying off £295,000 of the loan in 2002.
A Number 10 spokesman said the chief whip had spoken to Mr Chapman, who represents Wirral South in Merseyside.
"He is investigating documents provided by Mr Chapman and will seek further clarification from him and the Fees Office in the morning," said the spokesman.
Mr Chapman's allowances were scrutinised by the Fees Office, part of the Resources Department within the House of Commons.
The officials are ultimately responsible to the Speaker and their work is overseen by committees of MPs.
BBC political correspondent Carole Walker said the "latest twist" in the expenses controversy put the spotlight on the Fees Office.
"Mr Chapman is not the first to say that everything he claimed was done on the advice of the Commons authorities," she said.