The dispute centres around claims by the workers that they were asked not to turn up at the shipyard during a ship naming ceremony on Thursday afternoon.

The workers, who are paid by the hour, objected to this.

A Harland & Wolff spokesperson said that the workers appeared to be upset over not being required to work during the ceremony.

He added that the dispute centred on pay and conditions.

H&W is anxious to find new work in defence industry

The naming ceremony for a Texan oil-drilling vesse took place amid growing unease over future prospects for the Belfast shipyard.

The Glomar CR Luigs, and a sister ship for the same company, Global Marine, are the last firm orders which the company has.

The second vessel is also nearing completion and the shipyard is now seeking to return to defence industry work for the first time in a decade.

Harland & Wolff has tendered to build two landing craft for the Royal Navy and is trying to win work on two new aircraft carriers as part of a consortium.

The company says it has also been shortlisted for an oil drilling ship for Shell and is hoping to win a contract to build the hull of passenger vessel.

Return to profit

Earlier this year Harland & Wolff bucked the trend in the depressed British shipbuilding industry by announcing a return to profits.

The shipyard managed to turn a loss of £1.5m in 1998 into a £5m profit this year.