The Government has asked the Anglo-Irish Secretariat in Belfast to prepare a full report on rioting in Portadown, Co Armagh, on Saturday night.
Irish officials will now contact the Northern Ireland Office and local community leaders to establish precisely what happened.
In the meantime, following representations from the SDLP and Sinn Fein, the Taoiseach, Mr Ahern, has repeated that an alternative should be found for the use of plastic bullets to control crowds. A spokesman for the Taoiseach said last night that Mr Ahern was on record as saying the thrust of the Patten report was that a replacement should be found for plastic bullets.
During Saturday's disturbances in Portadown, 57 RUC officers were hurt. The violence followed a parade by junior members of the Orange Order along the lower end of the nationalist Garvaghy Road. At the height of the trouble, RUC officers in full riot gear were attacked by acid bombs, petrol bombs, bricks and bottles thrown by nationalist youths.
Police officers responded by firing a number of plastic baton rounds at the rioters.
The trouble started after the RUC, supported by soldiers of the British army's Parachute Regiment, deployed along a 200-metre stretch of the Garvaghy Road in preparation for the parade of junior Orangemen. As police vehicles blocked the road they came under fire from nationalist youths throwing bottles and stones.
The violence escalated as the security forces attempted to withdraw from the area after the Orange parade dispersed. At this stage a petrol bomb exploded on top of an armoured police Landrover. RUC officers responded by firing a plastic baton round into the crowd.
The intensity of the missile-throwing increased and RUC officers baton-charged the 200strong crowd. As police Landrovers attempted to force a path into the crowd, fierce hand-to-hand fighting between the RUC and nationalist residents broke out.
Further baton rounds were fired at the rioters and a number of non-participants were injured in the exchanges. So intense was the violence that RUC officers were forced to withdraw back down Garvaghy Road under a barrage of stones, acid bombs and bottles. A number of nationalist youths then pushed a car into the line of police vehicles and set it alight. The junior Orange parade along Garvaghy Road has a history of inflaming tensions in the area. In 1999, 13 police offers were injured after violent clashes involving nationalist and loyalist protesters.
Yesterday, nationalist sources in Portadown said Saturday's riot was provoked by RUC heavy-handedness and loyalists breaking parade restrictions.
Local Sinn Fein MLA Dr Dara O'Hagan accused the Parades Commission of ignoring appeals to reroute Saturday's march further away from Garvaghy Road and instead bowing to pressure from the Orange Order.
The SDLP Assembly member, Ms Brid Rodgers, said she was concerned at the RUC use of plastic baton rounds and said she had raised the issue with the Irish Government.
The RUC has defended police handling of the situation. Assistant Chief Constable Stephen White condemned the Garvaghy Road violence and said that due to the extent of the rioting police had no other option but to resort to the use of plastic baton rounds.
The Portadown violence was also condemned by the North's Security Minister, Mr Adam Ingram. "A mob that attacks with paving stones, petrol and acid bombs is not engaged in anything that can be called `legitimate protest'. Once again the police have borne the brunt of that mob violence and over 50 officers have been injured as a consequence".
The Sinn Fein president, Mr Gerry Adams, renewed his call for the banning of plastic bullets. He said a "provocative parade" had sparked the disturbances. "I defend the right of the Orangemen to march. . . but why not just march where they can have a nice time, where people are glad to see them and leave other areas where there is sensitivity, or where they are downright unwelcome, alone?"