A DUP Assembly member has claimed Garda detectives will replace the RUC close protection unit assigned to the President, Mrs McAleese, when she visits two nationalist areas in the North on Thursday.
Mr Ian Paisley jnr claimed the Chief Constable had confirmed to him that the switch, which would affect visits to Strabane and west Belfast, had been made at the request of the Irish Government.
"It is a deliberate snub to the RUC and its close protection unit who are more than capable of doing the job, but are being undermined in a disgraceful episode of appeasement of nationalists and republicans in those areas," he said.
"This move, if it is permitted to go ahead, is a disgraceful and inappropriate intervention by a foreign government in the operational activities of the RUC, all at the behest of an anti-police elements in Northern Ireland."
The arrangements are expected to be in place when the President visits community centres in Andersonstown, west Belfast, and Strabane, Co Tyrone. When President Clinton visited Belfast in 1985 he brought an estimated 150 protection personnel with him, while members of the British royal family also bring their own security staff.
An RUC spokesman said: "It would be normal for the President to be accompanied by members of her staff, which would include members of the Garda Sioch ana. All VIP visits receive RUC attention. However, we do not discuss details of security arrangements."
A Garda spokeswoman said: "We would not speak about operational matters at all." A spokesman for the Government said the President's security in Northern Ireland was always decided by the RUC.
A spokeswoman for the President said she always received RUC protection in the North. She added that the President had personal protection officers who would be members of the Garda and who travel with Mrs McAleese.