Speaker Margaret Wilson wants a Cabinet minister to be in charge of parliamentary spending - instead of doing the job herself.
But National is leaning towards self-policing and putting MPs back in charge of the system.
Concern over who should be in charge was heightened after Auditor-General Kevin
Brady found that political parties had unlawfully spent $1.2 million of taxpayers' money at the last election.
Also, a triennial review of Parliament's spending headed by businessman John Goulter has been highly critical of the way the system has been running.
Margaret Wilson, appearing before Parliament's finance and expenditure committee yesterday, clearly does not want the job.
Allegations of bias in her decision-making had been made since "day one".
Responsibility for spending was given to the Speaker only after the law was changed in 2000. Before that, Parliament's spending was overseen by a "commission" of MPs, the Parliamentary Service Commission. It was chaired by the Speaker but the power lay with the commission.
Margaret Wilson said that in Canberra a whole department, with its own minister, was devoted to looking after MPs' services.
"It certainly seemed to me to be the most efficient of the processes because you had expertise and experience and by and large there were not allegations made ... of partiality in terms of how members' expenses were dealt with."
National deputy leader Bill English said later: ' "Just putting a minister in hands control to the executive - and for the Opposition that is a step too far."
The structure had worked fine, he said, before the law was changed in 2000. "The responsibility was with the whole [commission], not the Speaker, and what that created was self-policing because they had access to all the information and you couldn't step out of line because the other parties could see what you were doing."
Act leader Rodney Hide said Speaker Margaret Wilson had done a great job trying to bring Parliament's funding into the 21st century.
The commission, which is now just an advisory body to the Speaker, had gone through 15 years of minutes to try to work out what the rules had been.
"It was basically run as an old boys club where the rules were very loose," said Mr Hide. "It has been a hell of a job."
