DUP politician Gregory Campbell has become the latest MLA to confirm that he rents his constituency office from a family member
The East Londonderry MLA's Coleraine office is owned by his wife. The rent, claimed from Stormont allowances, is £12,600 per year.
Mr Campbell said an estate agent was consulted on the rental valuation for the Coleraine premises.
He said he would be happy to support valuations being fixed by Assembly-appointed estate agents, if such a proposal emerged from the current debate on expenses.
"In the interests of openness and transparency, I think it would be a good idea," he added.
MLAs and MPs are permitted to rent offices owned by their parties.
Sinn Fein has confirmed that two of its west Belfast MLAs - Paul Maskey and Sue Ramsey - are currently renting offices in the party's Connolly House HQ on the Andersonstown Road.
A third, Fra McCann, was based there until last September.
A Sinn Fein spokesman said: "Fra McCann was originally the sole MLA tenant at an annual rent of £13,500. Connolly House underwent extensive restructuring and Fra moved out in September of last year and only drew down rental to that point."