SIPTU have applied to the Irish Congress of Trade Unions for approval for an all-out strike at Waterford which could cripple sea container traffic in the south-east.
Six boatmen who transport pilots to ships navigating the Suir from Dunmore East have been on strike for a week over pay and conditions.
SIPTU Regional Organiser, Mr Davy Lane, said yesterday the union has no option but to escalate their strike action.
"We've decided that in order to increase pressure on management in relation to our claim we have no other choice. Our members are looking for their working conditions to be improved.
"However, management came back with a whole new working regime, which is basically unacceptable to our members."
The union official said an all-out strike could create difficulties but said he feared it is now unavoidable.
"Management gave our members three options at talks on Wednesday but all were unsatisfactory. Management are saying that business is unaffected by the industrial action to date but if we mount an all-out picket then there will be a major impact on the port. No one wants to go down that road but unfortunately we have no other choice." Port management and SIPTU representatives met twice with the Labour Relations Commission prior to the strike but talks broke down last week.
Pickets were placed at Dunmore East, where the boatmen are based, and a further picket is in place at the main port in Belview since Monday last.
The chairperson of the Port of Waterford, Cllr Ben Gavin, said yesterday that they are willing to resume negotiations.
"We are open to re-enter talks on the measures in the package, which are progressive, forward-thinking and in line with best working practices."