WASHINGTON - THE confirmation hopes of US treasury secretary designate Timothy Geithner were thrown into doubt on Tuesday over questions about tax records and the immigration status of a former housekeeper.

President-elect Barack Obama's spokesman Robert Gibbs issued a statement admitting Mr Geithner had made a 'common mistake' on his taxes and was unaware the housekeeper's authorisation had expired during her last three months on the job.

But Mr Gibbs called on the Senate to confirm Mr Geithner, saying he was the right man to lead the US economic recovery.

Earlier, the Wall Street Journal reported on its website that senators were probing suggestions that a housekeeper who worked briefly for Mr Geithner had not had proper immigration papers.

It also said senators were concerned that Mr Geithner did not pay social security and Medicare taxes for 'multiple years'.

'The President-elect chose Tim Geithner to be his Treasury Secretary because he's the right person to help lead our economic recovery during these challenging times,' Mr Gibbs said.

'He's dedicated his career to our country and served with honour, intelligence and distinction. That service should not be tarnished by honest mistakes, which, upon learning of them, he quickly addressed.

'We hope that the Senate will confirm him with strong bipartisan support so that he can begin the important work of the country.'

The Journal quoted people familiar with the case as saying Mr Geithner's housekeeper's papers had expired, but she went on to get a green card to work legally in the United States and was not prosecuted.

The paper also said that while Mr Geithner worked for the International Monetary Fund between 2001 and 2004 he apparently omitted to pay Social Security and Medicare taxes, an oversight related to his self-employed status.

Once the Internal Revenue Service notified him of the error he paid up, with interest, the paper said.

On the face of it, the transgressions seem minor but key nominations of both presidents George W. Bush and Bill Clinton foundered over controversies over immigration papers and tax obligations relating to domestic help.

Mr Obama believes Mr Geithner will bring international experience, the insight of a Washington insider and markets technocrat to the key post at a time of acute, global economic peril.

The well-traveled president of the New York Federal Reserve has been at the sharp end of US authorities' battle to shore up panicky financial markets by overseeing the central bank's explosion of intervention in recent months.

The 47-year-old - who also serves as vice chairman of the policy-making Federal Open Market Committee - was a key player in negotiations which, just before midnight on Sunday, resulted in a US government rescue plan for ailing banking giant, Citigroup. -- AFP