Trade union leaders yesterday said they were growing increasingly anxious at the news blackout surrounding the continuing talks between the Belfast shipyard Harland & Wolff and its US customer Global Marine on a dispute between the two.

The chairman of the senior shop stewards committee, Mr Bobby Moore, said the unions were "very disappointed and deeply concerned" that no agreement had yet been reached between the two companies. He added: "The trade unions have made it clear to both parties that any agreement reached between the parties must contain the guarantee that H & W is assured of continuing as a viable shipbuilding entity. We will not accept a position that only guarantees the completion of the current contract for the two drill ships."

Commenting on speculation that the vessels could be finished in a different shipyard should the two companies not reach a deal, Mr Moore said: "In circumstances where any attempts were made to move the ships from Belfast without agreement having been reached, the trade unions would strongly oppose this and seek the support of the people of Northern Ireland to ensure that the contracts would be finished in Belfast by H & W." The H & W board is understood to be considering an offer tabled by the president of Global Marine, Mr Robert Rose.

A Global Marine board meeting at the company's Texas headquarters was expected to take place late yesterday.

The dispute between the Belfast shipyard and its US customer centres on an invoice for £133 million sterling (€208.5 million) lodged by the shipyard for extra work it allegedly carried out on the two vessels currently under construction for Global. A cross-party group of members of the Northern Ireland Assembly has sent an open letter to Global Marine calling for its "understanding and support".