Dublin Port Company has described as "grossly misleading" claims that it suspended shore-based maintenance workers because they refused to operate tug boats during recent storms.
The Technical Engineering and Electrical Union (TEEU) has claimed that five shore staff, who had no training as crew members, were suspended when they refused to man tug boats this week.
Industrial action at the port is likely if the suspension is not lifted by Monday, the union said.
Two of the men, who are part of the fitters and electricians team in the company's maintenance section, worked on the boats under protest last weekend despite having no training, no ships' papers and no life jackets, safety harnesses or survival suits, the TEEU said.
The union's general secretary Arthur Hall said the company appeared to have assigned the men to operate the boats during bad weather because of staff shortages.
"During a week when seven fishermen have lost their lives at sea it is extraordinary that a State-owned company is asking fitters and electricians to double up as seamen.
"These men are being told to operate tugs that guide and tow vessels into Dublin."
Assigning the fitters as crewmen was in direct contravention of a previous company directive that shore workers could not stand in for tug boat crew because of safety concerns.
"If anyone is suspended in these circumstances it should be the management personnel who made this irresponsible decision," Mr Hall said.
Dublin Port Company said the union's claims were "false and grossly misleading" and have come as a "huge shock". It has vehemently denied that any staff were suspended for refusing to operate tugs, however it admitted that some staff had been suspended.
"Their suspension resulted from their refusal to comply with a reasonable management request to undergo additional ongoing training," it said. The additional training had nothing to do with operating or manning boats, and there were no health and safety issues involved in the suspensions, the company said.
"Dublin Port Company wishes to confirm that no member of staff referred to in the TEEU statement were asked to form part of a crew of a tug.
"It is, therefore, incorrect for the TEEU to suggest that fitters or electricians who are members of their union have been asked to operate tugs in Dublin Port."
It added that all its tugs carried the full complement of safety equipment.
The TEEU has accused the company of being disingenuous in its response and said industrial action will follow if the situation is not resolved on Monday.
