The parliamentary sleaze watchdog has been urged to investigate Culture Secretary Maria Miller's expenses claims towards a home used by her parents.
Labour MP John Mann complained to John Lyon, the Parliamentary Commissioner for Standards, after it emerged Mrs Miller had allowed her parents to live at a property on which she claimed more than £90,000 in second home allowances during the last parliament.
Mr Mann claimed that the arrangement was "identical" to that of former Labour minister Tony McNulty, who in 2009 was required to pay back more than £13,000 in expenses claimed on a second home occupied by his parents.
In that case, the Commissioner said Mr McNulty had effectively "subsidised" his parents from the public purse by allowing them to live rent-free.
Aides to Mrs Miller insisted the two cases were different, that her arrangements had been audited and cleared twice and that she had acted in accordance with advice from the fees office, which administered MPs' expenses until 2010.
Mrs Miller told Sky News: "My expenses are absolutely in order. They've been audited twice."
Her expenses claims were detailed in The Daily Telegraph, which said she had claimed £90,718 - almost the maximum permitted - between 2005 and 2009 towards mortgage payments, bills and other costs. Mrs Miller's parents, John and June Lewis, had apparently been living there since selling their home in Wales in 1996.
Mr Mann wrote to the Commissioner, registering a complaint. The MP said: "Maria Miller's circumstances are identical to those of Tony McNulty who allowed his parents to live in his second home rent free and the Committee on Standards and Privileges ruled that he had broken the rules. It was a dreadful scandal in 2009 when the corrupt expenses claims were first exposed and it remains a scandal that some of our MPs have still not put their houses in order and voluntarily paid back monies they should not have claimed."
A spokesman for Mrs Miller said her parents lived with her as dependants under the rules put in place since the Independent Parliamentary Standards Authority (Ipsa) was put in charge of MPs' expenses in 2010.
"Mrs Miller's elderly parents have lived with her family for nearly two decades, an arrangement that has been in place long before she was elected as an MP seven years ago. They are dependants under Ipsa rules," the spokesman said. "Her financial arrangements have been audited twice, and have been found to be wholly proper and above board. She sought guidance from the fees office in regard to her expenses and acted in accordance with that. Any suggestion her arrangements are questionable is simply untrue."