In a report on evidence it says it obtained since Galloway testified in May, the subcommittee said on Monday that Galloway personally solicited and received eight oil vouchers from the Saddam Hussein government between 1999 and 2003.
It also said that Galloway's wife, and a political campaign run by Galloway, both received money generated by the oil allocations; and that Saddam's government took $1.6 million in kickbacks in connection with the Galloway vouchers.
In denying such benefits in his May testimony, the report said, "Galloway knowingly made false or misleading statements under oath before the subcommittee".
From London, Galloway responded: "I am demanding prosecution, I am begging for prosecution."
He told Sky News: "I am saying if I have lied under oath in front of the Senate, that's a criminal offence.
"Charge me and I will head for the airport right now and face them down in court as I faced them down in the Senate room."
Top UN officials are also accused
of oil-for-food scheme benefits
Led by Senator Norm Coleman, the investigative arm of the Committee on Homeland Security and Government Affairs has been studying reports of corruption surrounding the 1996-2003 UN Iraq oil-for-food programme.
Coleman's group has focused its attention on individuals it believes took illegal benefits from the programme, which was aimed at allowing sanction-hit Iraq to sell a limited amount of oil to buy food and medicine for its population.
Galloway accused Coleman of seeking revenge for his "humiliation" at the May hearing.
"Because I publicly humiliated this lick-spittle senator Coleman - one of (President George W) Bush's right-hand men - in the US Senate in May, this sneak revenge attack has been launched over the last 24 hours," he said.
Besides Galloway, Coleman's committee has fingered senior officials at the UN, and top Russian and French politicians, of taking money or oil allocations from the programme.
Two former high-ranking French diplomats - including the representative to the United Nations between 1991 and 1995 - have been placed under criminal investigation by a French judge looking into the matter.
In its newest report, the Coleman committee added new evidence for its earlier accusations that Galloway, an outspoken opponent of US policy in Iraq, worked with Jordanian businessman Fawaz Zuraiqat to obtain money from an oil-for-food programme oil allocation.
Citing bank documents, records from the former Saddam government, testimony from Saddam's former deputy prime minister Tariq Aziz, and information from two unidentified oil traders, the report said that Galloway's Mariam Appeal political campaign reaped at least $446,000 from oil allocations.
"Isn't it ironic that on the one hand we are told that the likes of Tariq Aziz and Saddam Hussein are homicidal maniacs, and on the other they are the most trustworthy people in the world when it comes to providing testimony against George Galloway?"
It also said his now-estranged wife Amina Abu-Zayyad got about $150,000.
According to Aziz, Galloway visited Baghdad in November 1999 on a tour raising money for the Mariam Appeal.
Aziz said Galloway was awarded oil allocations for resale, eventually totalling about 23 million barrels, to help the appeal, with a profit margin of 10 to 15 cents per barrel, according to the report.
It also said that the main conduit for trading the oil allocations was Zuraiqat, a personal friend of Galloway, who eventually paid Saddam's officials $1.6 million under the table for the vouchers.
Noting that they had not yet seen the Senate report, Galloway's spokesman reiterated his denial of the original charges and the newest one of having deliberately given false or misleading testimony to the subcommittee.
Galloway "has challenged Coleman and the committee to charge him with perjury. He will get on the plane to the US as soon as they do that", Roy McKay said.
He also questioned the subcommittee's sources.
"Isn't it ironic that on the one hand we are told that the likes of Tariq Aziz and Saddam Hussein are homicidal maniacs, and on the other they are the most trustworthy people in the world when it comes to providing testimony against George Galloway?" McKay asked.