Ulster loyalists should reconsider holding a mass protest in central Belfast this Saturday because police resources are being dangerous stretched by republican dissidents, rank and file officers have warned.

Up to 10,000 loyalists along with about 40 marching bands are expected to march into Belfast city centre on one of the busiest shopping days of the year. They are staging a demonstration against the continued restrictions on the union flag flying over Belfast city hall.

The deputy first minister, Martin McGuinness, claimed in the Stormont parliament on Tuesday that loyalist terror group the Ulster Volunteer Force was orchestrating the planned protest.

The Police Federation of Northern Ireland on Wednesday urged the loyalists to "reconsider their position" in the light of recent attacks by hardline republican groups, including an attempt to bomb one of Belfast's biggest police stations earlier this week.

There have been 16 different bomb attacks by the new IRA and other groups opposed to the peace process in recent weeks across Northern Ireland.

Terry Spence, the federation's chairman, said: "I do respect the right to parade, I do respect the fact the Parades Commission has made determinations that they can do it, but I would ask them to look at where we currently are with this very severe dissident republican threat, at the upper end of severe, and the fact the police are trying their best under hugely difficult circumstances to bring the perpetrators to justice.

"This parade will bring further distraction from carrying out our duties. I would ask them to consider their position bearing in mind the 16 bomb attacks."

Spence warned that policing the parade "will distract well over 1,000 police officers to deal with the potential fallout from the demonstration".

"Police resources are already stretched, and Saturday will stretch them to the limit," he added.

Spence said of the dissident republican threat: "There has been a consolidation of these disparate dissident republican groups co-operating more with each other as well as the fact that there is a drift from mainstream republicanism to the dissident camp."