George Galloway has rejected allegations he received more than £1m from Saddam Hussein.
Mr Galloway was expelled by Labour for remarks about the war
The Sun said the rebel MP's name was on a list of individuals and firms alleged to have received vouchers for barrels of oil from the ousted Iraqi leader.
Glasgow Kelvin MP Mr Galloway says he is the victim of a smear campaign.
"It is perfectly easy to establish no barrel of oil or voucher for a barrel of oil has ever been given to me or been bought and sold by me," he said.
He added, during an interview with GMTV: "This is a trumped-up smear campaign."
Evidence presented to the US Congress had suggested the vouchers were handed to Mr Galloway's Jordanian intermediary, Fawwaz Zureiqat.
They could be redeemed for money without any oil being involved.
The row over alleged payments is linked to the UN-administered oil-for-food programme in Iraq.
The now defunct scheme was designed to help Iraq buy humanitarian goods and ease the impact of sanctions.
The UN Security Council has approved an investigation into reports of massive corruption in the scheme.
Mr Galloway was an outspoken opponent of the Gulf war and some of his comments prompted his expulsion from the Labour Party.
He has since formed a "unity coalition" to challenge New Labour.
When he launched the political grouping he said he wanted to "unite the left, the peace movement, the anti-war cause, the Muslim community in Britain, progressive people of all parties and none, to fight New Labour in the European elections in June in England and Wales
June's European election".
Mr Galloway expulsion from Labour came after remarks he made during an interview with Abu Dhabi television in which he branded Mr Blair and George W Bush "wolves" for attacking Iraq.
Last month he accepted damages and a public apology over an article in a US newspaper alleging he received cash from Saddam.
The Christian Science Monitor conceded a set of documents on which its story was based was "almost certainly" fake.
After the hearing at London's High Court, Mr Galloway said the damages were a "complete vindication" of his denial that he had "received one thin dime from
the Iraqi regime, from Saddam Hussein".