At least 100,000 people have taken part in protests around the country in support of Irish Ferries workers.
The national day of protest was called by the Irish Congress of Trade Unions, which is demanding Government action to combat exploitation of migrant workers and the displacement of jobs.
There were rallies in Dublin, Cork, Waterford, Limerick, Galway, Sligo, Athlone and Rosslare.
Gardaí estimate that 40,000 people took part in the march in Dublin, although organisers claimed the figure was far higher. Gerry Adams of Sinn Féin, Pat Rabbitte of Labour and John Gormley of the Green Party participated in the march in the capital.
Staff on board the Isle of Inismore in Pembroke and the four engineers holed up in the ships control room have said they were overwhelmed by the level of support shown by marchers in today's rallies.
Bus and rail services were disrupted during the protest but returned to normal for evening rush hour.
Updated information is available at www.irishrail.ie and at 1850 366222.
After earlier disruption to the Luas Red Line, both Luas lines are now running as normal.
ISME critical of day of protest
The Irish Small & Medium Enterprises Association, ISME, has strongly criticised the National Day of Protest.
In a statement, the ISME Chief Executive, Mark Fielding, said the protest is undermining the industrial relations process in this country.
Mr Fielding said it has very little to do with the Irish Ferries dispute and is in fact an attempt by the unions to influence negotiations in advance of any new national pay agreement.
Speaking on RTÉ Radio’s Morning Ireland, the SIPTU President, Jack O'Connor, said the rallies would give workers the chance to take a stand.
While the Director General of IBEC, Turlough O'Sullivan, said there is nothing to be gained from disrupting business and the general public.
Mr O'Sullivan said that whatever one's views on the Irish Ferries dispute, nothing could justify calling a national work stoppage when discussions are already underway in a bid to resolve the row.
LRC talks adjourned without agreement
Last night, talks at the Labour Relations Commission between union representatives and management at the ferry company adjourned without a resolution.
The latest negotiations finished shortly after 2.30am.
The Chief Executive of the LRC, Kieran Mulvey, said he would be contacting both parties to establish a basis on which negotiations could recommence.
Union officials said it would be unlikely they would be available for negotiations today because of the day of protest.
However, they did not rule out returning to the LRC on Saturday or on Monday.