George Galloway is preparing to appear before a US Senate committee that has accused him of receiving oil options from Saddam Hussein's regime.
George Galloway has dismissed the allegations as ridiculous
The Respect MP for Bethnal Green & Bow has travelled to Washington for the hearing, but has dubbed the committee's report as "a schoolboy dossier".
The committee alleged Mr Galloway and French politician Charles Pasqua received oil rights from the Iraqis.
Respect has said a document used against Mr Galloway is forged.
Mr Galloway appeared relaxed and jovial when he arrived in the US, but made it clear he was going to go on the offensive.
"Get a ringside seat," was his advice to journalists.
'Full of holes'
Mr Galloway has said the Senate investigative committee's report is "full of holes, full of falsehoods".
"I am not expecting any justice from the innards of the US government but I want to appear not as the accused but as the accuser.
"They seem blissfully unaware that for people in the rest of the world the villains in the piece in Iraq are them."
He said earlier: "The truth is I have never bought or sold a drop of oil from Iraq, or sold or bought a drop of oil from anybody.
"If I had, I would be a very rich man and the person who made me rich would already be in the public domain."
The United Nations-backed oil for food scheme enabled Saddam Hussein to export oil to pay for essential humanitarian aid to help the Iraqi people cope with UN sanctions imposed in 1991.
The options to buy barrels of Iraqi oil were alleged to have been given as rewards for supporting Saddam Hussein.
The former Iraqi leader sold the vouchers at below market prices to favoured parties, who were able to sell them on at profit.
On Monday Russian politician Vladimir Zhirinovsky denied the committee's accusations that he accepted millions of dollars in Iraqi oil allocations.
Meanwhile, a spokesman for Mr Galloway's Respect party told a press conference the document used by the Senate hearing was a forgery.
The spokesman said: "The actual first document, we don't know where it is, they don't know where it is and all they have is a photocopy handed over by an unnamed source."
Typographical analysis showed Mr Galloway's name was in a different typeface, a lighter shade and at a different angle to the rest of the document, he said.
The spokesman suggested Mr Galloway's name had been stuck to the bottom of the list, and the document photocopied.
He also cited testimony from an Iraqi who claimed he forged lists of people who profited from the oil for food scheme.
In December, Mr Galloway won £150,000 in libel damages from the Daily Telegraph over its separate claims he had received money from Saddam's regime.
The MP had denied ever seeking or receiving money from Saddam's government, which he said he had long opposed.
Last month the newspaper won permission to appeal against the ruling to pay the damages, plus £1.2m in costs.
The Senate committee's report also accused Mr Pasqua of receiving oil rights from Iraq, something he has vehemently denied.
The report claims both he and Mr Galloway were given potentially lucrative oil allocations as a reward for their support in calling for sanctions against the regime to be loosened.