Senior politicians from Belfast, Dublin and London are to meet next week to discuss the Union flag protests.

More than 40 days of road blocks and sporadic violence by loyalists have failed to produce a solution to the dispute over restrictions on the flying of the emblem.

Stormont First Minister Peter Robinson and his deputy Martin McGuinness will join Northern Ireland Secretary Theresa Villiers and Ireland's Tanaiste (deputy leader) Eamon Gilmore, sources said.

The demonstrations against Belfast City Council's decision to hoist the Union flag from the City Hall only on designated days like royal birthdays have brought many parts of Northern Ireland to a standstill.

Non-lethal baton rounds and water cannon have been used by police as they faced attack with petrol bombs, fireworks and other missiles in greater Belfast in recent weeks by children as young as eight.

There were region-wide road blocks in Northern Ireland on Friday night, forcing many office workers to leave Belfast early and making the city centre relatively quiet. A pipe bomb was also discovered on one arterial route and many others were closed because of protests, police said.

Around 70 police officers have been injured and more than 100 arrests made during weeks of trouble, the Police Service of Northern Ireland (PSNI) said.

Businesses in Belfast's city centre have struggled to cope, with many reporting lost trade, and the Confederation of British Industry (CBI) warned some investors may think again.

A doctor was prevented from attending a terminally ill cancer patient because of loyalist road blocks in south Belfast, it was revealed.

The GP was travelling to a home call with the sick man when he was stopped twice by crowds of demonstrators who blocked the road. Police asked them to move but they refused, nationalist SDLP MLA Conall McDevitt said.