George Galloway has rejected claims he lied under oath to the US Senate committee which accused him of receiving oil cash from Saddam Hussein.
The Respect MP ridiculed the senators' claims during a hearing in May.
Now they say fresh evidence links him and his estranged wife to Iraq's oil-for-food programme. Mr Galloway and his wife both deny the allegations.
Mr Galloway said: "I am ready to fly to the US today... to face such a charge (perjury) because it is simply false."
The US Senate committee claims to have found £85,000 in Iraqi oil money in the bank account of his estranged wife Dr Armineh Abu-Zayyad.
The MP could face criminal charges if he is found to have given false testimony to the committee on 17 May.
During that combative performance he defended himself against accusations by senators that he received credit to buy Iraqi oil.
One of the main allegations raised by the senate sub-committee was that Mr Galloway received oil allocations with the assistance of Fawaz Zureikat.
Mr Zureikat, who was chairman of the Mariam Appeal set up by Mr Galloway to help a four-year-old Iraqi girl with leukaemia, has strongly denied making any arrangements linked to oil sales on behalf of the MP.
The senate committee's new report accuses Mr Galloway of personally soliciting and being granted eight oil allocations totalling 23 million barrels from the Hussein government between 1999 and 2003.
It also says that his estranged wife received £85,000 in connection with one allocation of oil.
The committee alleges that at least £252,000 was funnelled to the Mariam Appeal through several allocations.
Republican Senator Norm Coleman, chairman of the committee, said documents it had uncovered were "the smoking gun".
He said that Mr Galloway had "been anything but straight" with the committee and he had sent a report to the US Department of Justice and to British authorities.
Mr Galloway, who has denied all suggestions he profited from told BBC Radio 4's Today programme: "The specific allegation against me is that I lied under oath in front of a senate committee.
"In this case the remedy is clear - they must charge me with perjury and I am ready to fly to the US today, if necessary, to face such a charge because it is simply false."
Perjury in the US carries a penalty of up to five years in prison and a £140,500 fine.
The Bethnal Green and Bow MP also launched an attack on the senate investigators.
"They have been cavalier with any idea of process and justice so far, but I am still willing to go to the US and I am still willing to face any charge of perjury before the senate committee," he said.
In the committee's report Dr Abu-Zayyad is specifically quoted denying she received any money.
Asked whether she or Mr Galloway had benefited from Iraq oil sales, she said in writing: "I have never solicited or received from Iraq or anyone else any proceeds of any oil deals, either for myself or for my former husband."
BBC Washington correspondent Justin Webb said the latest developments meant the senators' confrontation with Mr Galloway had "reached a new and more serious stage".
Mr Galloway has always denied funds from the sale of Iraqi oil were funnelled through the Mariam Appeal.
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 paper is currently awaiting the result of its appeal against that ruling.