The Progressive Unionist Party leader David Irvine has said he will never again meet the commission which monitors paramilitary activity.
David Irvine said the report omitted important information
The Independent Monitoring Commission's first report highlighted the levels of paramilitary activity by republican and loyalist groups.
The PUP is facing financial sanctions because of its reported links to the loyalist paramilitaries, the Ulster Volunteer Force and the Red Hand Commando.
Financial sanctions are also to be imposed on Sinn Fein over continued IRA violence.
The commission accuses the PUP of not doing enough to prevent the illegal activities of the paramilitary organisations.
The IMC report linked the UVF to murder, major crime, so-called paramilitary punishment attacks and to a bomb placed outside a Belfast bar on St Patrick's Day.
The commission are due to deliver a second report later this year
The Red Hand Commando group was accused of being deeply involved in drug dealing, something its leadership denies.
However, David Ervine believes important information has not been included in the report.
"If the IMC report was meant to give a clear and precise understanding of the state of paramilitarist attitudes and violence within Northern Ireland, then there was a hell of a lot left out," he said.
"I met them with a group of people who were deeply open, very upfront and tried to consult in a way that was ensuring a more full picture of the circumstances relating to UVF and Red Hand Commando violence.
"Not one word of any of that inter-action between the IMC appears."
He added: "The Progressive Unionist Party leadership as a whole does not determine these activities and may not be in a position to ensure prevention of them.
"But it can exert appreciable influence," Mr Ervine told BBC Radio Ulster on Monday.
'Not be commenting'
This information includes a decision by the UVF to disarm and disband the unit responsible for the murder of John Allen in Ballyclare last November.
The party has also directly urged the government to deal with criminals in the loyalist community.
Mr Irvine is due to meet the Secretary of State, Paul Murphy, on Tuesday but he has said he will never again meet with the IMC.
The commission has made clear it will not be commenting beyond the content of its report.
The four man body, which began operation in January, was originally due to report on loyalist and republican paramilitary activity every six months.
This timetable was dramatically altered in February following an incident involving Mr Tohill, which Chief Constable Hugh Orde immediately blamed on the IRA.
The commission is a crucial element in the two governments' plans for restoring devolution, which was suspended in October 2002 amid allegations of IRA intelligence gathering at Stormont.