Maria Miller has said one of the two audits into her expenses had been carried out by former civil servant Sir Thomas Legg - who was called in to review all MPs' claims at the height of the expenses scandal - and the other by the Conservative Party.
Mrs Miller claimed second home allowances of £90,718 - almost the maximum permitted - between 2005 and 2009 towards mortgage payments, bills and other costs relating to a house where her parents had apparently been living since 1996.
Asked by the Evening Standard whether Sir Thomas was aware that her parents were living at her designated second home, Mrs Miller said: "I obviously spoke to the Fees Office about my claims and they were happy that everything was in order."
Questions about Maria Miller's expenses have drawn the Culture Secretary into a further row about her office's dealings with the Daily Telegraph, whose investigation led to the commissioner's inquiry.
An aide to Mrs Miller was reported to have called the newspaper and said she wanted to "flag up" the Cabinet minister's connection to press regulation during discussions about a story on the Cabinet minister's expenses.
Downing Street's top spin doctor, Craig Oliver, also mentioned the Leveson press reforms in a telephone call to the Telegraph's editor.
No 10 insisted yesterday that Mr Oliver was highlighting concerns about the way the Telegraph carried out its investigation into Mrs Miller's expenses claims, rather than attempting to threaten the newspaper.
David Cameron gave his backing to Culture Secretary Maria Miller amid the expenses claims.
Asked earlier today at a regular Westminster briefing if the Prime Minister had full confidence in Mrs Miller, a Downing Street spokeswoman said: "Yes, indeed he does."
Mrs Miller's expenses have been audited twice and found to be wholly proper and above board. Any suggestion to the contrary is simply untrue. She would fully co-operate with any inquiry.
The expenses investigation facing Maria Miller follows a complaint that she claimed more than £90,000 in second home allowances towards the cost of a house where her parents lived.
The complaint was lodged earlier this week by Labour MP John Mann, who claimed the arrangement was "identical" to that of former Labour minister Tony McNulty.
Mr McNulty was required to pay back more than £13,000 in expenses two years ago, after being found to have effectively "subsidised" his parents from the public purse by allowing them to live rent free in a second home.
Earlier this week Mrs Miller insisted that all of her expenses were "absolutely as they should be" in response to an article in The Daily Telegraph that reported the claims.
Culture Secretary Maria Miller is to have her expenses investigated by Parliamentary Commissioner for Standards John Lyon, his office has said.
Labour MP Simon Danczuk said the Telegraph report about Craig Oliver and Maria Miller contained "serious allegations":
These are serious allegations about two special advisers which call their integrity and professionalism into question.
If Craig Oliver threatened the Telegraph without David Cameron’s authority, that looks like an open-and-shut breach of the special advisers' code.
But if the Prime Minister authorised his special adviser to use the threat of Leveson Report discussions to discourage the publication of an embarrassing story, then that is potentially even more serious.
And the same applies to Maria Miller and her special adviser Joanna Hindley – if these allegations are true then one of them has broken the rules.
Downing Street defended its communications director Craig Oliver after he raised the issue of Leveson press reforms in a telephone call to the editor of the Daily Telegraph about a story it was planning to run on the Culture Secretary's expense claims.
Mr Oliver reportedly told editor Tony Gallagher "she (Maria Miller) is looking at Leveson at the moment" during the call last Friday.
The Prime Minister's spokesman said: "The Secretary of State had some concerns about the way that investigation was conducted. She set those out in a letter to the editor.
"Craig Oliver was simply reflecting those concerns."
Asked why the issues were brought up together, he said: "I think the point was being made that she had been spending some time in dealing with those issues in recent days.
"But what we were doing was raising some concerns about the investigation on that particular story."
Equalities Minister Maria Miller has postponed planned TV interviews this morning on same-sex marriage.
It comes amid a report in The Daily Telegraph that the Cabinet minister, whose primary position is Culture Secretary, claimed more than £90,000 for a second home where her parents lived.