Sinn Féin was meeting today with a new commission set up to monitor paramilitary activity.
A party spokesman said it would use the meeting with the Independent Monitoring Commission (IMC) to explain its opposition to the body, which he claimed was set up outside the terms of the Belfast Agreement.
Sinn Féin has claimed that the commission, which was formally constituted earlier this month, will be used to exclude republicans and others from democratic politics.
The IMC has a key role in determining whether the IRA and other paramilitaries have ceased activity mentioned in paragraph 13 of the Hillsborough Joint Declaration as "punishment" attacks, exiling, weapons procurement, targeting and intelligence gathering.
The IMC was criticised last week by senior Sinn Féin member Mr Alex Maskey. He was part of today's delegation, which also included Sinn Féin Assembly Group leader Mr Conor Murphy.
A spokesman said: "We will put very politely to the commission today why we are opposed to it and will not work with it."
The commission is also due to meet Northern Ireland's largest party after last November's Assembly election, the Rev Ian Paisley's Democratic Unionists.
The commission's members are former Northern Ireland Speaker Lord Alderdice; retired Irish civil servant Mr Joe Brosnan; Mr John Grieve who headed Metropolitan Police's anti-terrorist unit; and Mr Richard Kerr, a former deputy director of the CIA in the United States.