The DUP has criticised the Gaelic Athletic Association over a republican hunger strike commemoration to be held at a GAA ground in west Belfast.
The rally is commemorating the hunger strikes at the Maze prison
The rally is to be staged at Casement Park on 13 August.
The DUP's Gregory Campbell said the GAA had to decide whether it was a sporting or a "quasi-political" organisation.
However, Peadar Whelan from the National Hunger Strike Committee, which has organised the rally, said the event was non-party political.
The rally will commemorate the 25th anniversary of the hunger strikes at the Maze prison in which 10 IRA and INLA prisoners died.
The main speaker at the event will be Sinn Fein president Gerry Adams and it will be jointly compered by Sinn Fein MEP Mary Lou McDonald and fellow party member Toireasa Ferris, the mayor of Kerry.
Casement Park comes under the jurisdiction of the GAA's Antrim County Board and it is understood it has not objected to the rally.
However, the GAA's Central Council in Dublin discussed the matter on Saturday and agreed that the Casement Park rally would break the organisation's rules about staging political events.
"People have to decide within the Gaelic sporting fraternity: are they a sporting organisation or are they a quasi-political organisation," the DUP's Mr Campbell said.
"It's very clear the direction they appear to be going in in the past few weeks and some would say over the past few years.
"They have to decide, do they want to play sport or do they want to play at politics. They can't do both and maintain that they are purely a sporting organisation."
Mr Campbell added that there would be an uproar from nationalists if an event commemorating loyalist terrorists was staged at a cricket or rugby ground.
However, Mr Whelan said: "The commemoration is non-party political.
"It was organised by the National H-block Hunger Strike Commemoration Committee, not organised by any political party.
"Anyone, regardless of their party political affiliation is entitled to remember 10 brave men who died on hunger strike in 1981."
He said he believed grounds such as Casement Park "belonged to the people" as much as they belonged to the GAA.
The chairman of Antrim County Board, Dr John McSparran, was invited by BBC Northern Ireland Radio Ulster to talk about the matter, but he declined.