There were hopes an agreement would be reached by Friday between Kvaerner and GEC Marconi.

BBC Scotland business reporter Hayley Miller

Members of the government-appointed taskforce have met union officials at the yard and indicated that the delay was being caused by GEC.

John Wall, from the MSF union, said: "The problems don't lie, we understand, withKvaerner and certainly there is no way, shape or form we can criticise either the people on the taskforce or the government ministers.

The yard has run out of orders

"It would appear there is some fuzziness in GEC's thinking which has to be cleared up."

Union leaders are to hold talks with government ministers and the Ministry of Defence to try to work out the basis of an agreement by the end of next week.

The negotiations began earlier this year after Kvaerner announced it was selling its worldwide shipbuilding interests

Shipyard workers have backed the GMB and AEEU unions' resolution to try to save the threatened plant.

Around 250 employees are currently serving 90-day notice periods and the yard has run out of orders. Unions plan to ask Kvaerner next week to extend the notices.

If the GEC deal goes ahead it is likely that a contract to build two oil supply vessels for the Royal Navy would go to the Govan yard almost immediately.