BBC News reports that Harland and Wolff has entered administration, with accountancy firm BDO formally appointed to oversee the Belfast shipyard.
Having employed more than 30,000 at its peak, the move could now put 120 jobs at risk and spell the end of the iconic firm, best known for building the Titanic.
Unions representing workers have called for the shipyard to be renationalised.
They argue it would be cheaper for the government to keep the shipyard open.
However, the government has said the crisis is "ultimately a commercial issue".
The Northern Ireland Office said NI Secretary Julian Smith "understands the impact" uncertainty over the shipyard will have for workers and their families.
It said Mr Smith "had made it clear that he will continue to do everything he can to secure the future of this historic site and ensure workers' interests are protected".
More here on this development at the Queen's Island shipyard.