TUV leader Jim Allister has pledged to oppose a proposal to transfer the power to set MLAs' allowances back to the Assembly.
Mr Allister said that he would put forward an amendment to the motion to say there should be no change to the current arrangements which allow an independent body to determine allowances.
He will argue that only in exceptional circumstances - if the arrangements are causing "practical difficulties or inequities" - should the Assembly Commission issue guidance to the independent body, and this guidance must always be published.
On Tuesday, MLAs will debate the proposal that the power to set their allowances be returned to the Assembly Commission.
Mr Allister said there had been problems in the past that if an MLA retired, and their replacement wanted to keep the same office staff, those employees fell to the bottom of the pay scale rather than carry on at the point they had reached.
But only in such exceptional circumstances should the Assembly Commission become involved in the issue of allowances, he said.
In a letter to MLAs, Stormont speaker Alex Maskey said that the Assembly Commission had agreed on a twin-track approach, with an independent body continuing to set MLAs' salary and pension, but with the commission determining allowances which include staff and constituency office running costs.
The letter was signed by representatives from the five main parties.
Mr Maskey wrote: "If the Assembly passes this resolution to enable the commission to develop any new determination, the commission is mindful of the need to ensure that any provisions both comply with wider good practice and ensure value for money in the use of public resources.
"Rigorous processes will continue to be in place to ensure that members demonstrate (through invoices, etc) that all expenditure is in accordance with the rules regarding such allowances before they are reimbursed."
Mr Maskey added these are "complex matters" which the commission "considered in detail".
"The commission believes that this approach will retain the core principle of decisions on members' salaries and pensions being decided independently, while allowing some of the difficulties members have experienced in providing constituency services over recent years to be addressed," he wrote.