The body which monitors assembly member spending is "short on teeth", a senior MLA said.
Pat Ramsey claimed the Independent Financial Review Panel should have greater investigative powers and the right to issue more than one determination per assembly mandate.
Mr Ramsey said: "The problem is it is a bit short on teeth."
Last week a commissioner found Iris Robinson seriously breached code of conduct rules after borrowing £50,000 from two developers to give to her secret lover in 2008.
Kirk McCambley invested the money in opening a cafe on the River Lagan in South Belfast.
Commissioner Douglas Bain, who investigates alleged breaches of the MLA code of conduct, criticised the former DUP Strangford MLA but exonerated the first minister Peter Robinson of any wrongdoing.
Mrs Robinson suffered depression and withdrew from public life.
Judith Cochrane, representing the Assembly Commission which runs Stormont, said it was meeting soon to discuss the way forward.