A majority of Siptu workers at the Liebherr Ireland container plant in Killarney last night rejected Labour Court proposals aimed at resolving a four-year pay claim dispute and the result is likely to add greatly to worries about the future of one of Kerry's biggest firms.

A Siptu spokesman last night confirmed the proposals had been rejected and said a statement would be issued this morning.

The union, which represents less than half the 670 workforce, had taken industrial action in November and December in relation to a pay claim dating to 2009.

In early December, management accepted labour court recommendations to pay 2.5 per cent, back dated 18 months in return for work changes. However, the German-owned company issued stern warnings that its commitment to Killarney had been weakened as a result of actions by the Siptu workers, including staging a strike on a day when a long planned for visit by international industrialists was taking place.

Workers sought clarification on the changes in work practice and a vote was scheduled for yesterday.

The vote took place in the plant yesterday and sources suggested that just under 270 workers voted, with 160 rejecting the recommendations.

There has been intense concern about the impact of the industrial action by Siptu in Killarney. The 55-year-old plant is the largest single industrial employer in the county.

The average wage by skilled workers at the plant is €52,000, among the highest in the region.

Several satellite businesses, especially in the engineering line, along with transport and haulage are hugely dependant on Liebherr .

The Siptu organiser dealing with the dispute did not return calls yesterday or last night.

Work from the Killarney plant has already been transferred to the company’s Rostock plant because of disruption of overtime as part of the industrial dispute in late 2013.