By PA News Team.
Around 1,100 workers at P&O Ferries are to be made redundant as part of a plan to make the business "viable and sustainable", the company said.
The proposal involves more than a quarter of the workforce losing their jobs.
The company operates numerous Irish Sea crossings, including the Larne to Cairnryan and Dublin to Liverpool routes.
A spokesman for P&O Ferries said: "Since the beginning of the crisis, P&O Ferries has been working with its stakeholders to address the impact of the loss of the passenger business.
"It is now clear that right-sizing the business is necessary to create a viable and sustainable P&O Ferries to get through Covid-19.
"Regrettably, therefore, due to the reduced number of vessels we are operating and the ongoing downturn in business, we are beginning consultation proceedings with a proposal to make around 1,100 of our colleagues redundant."
Jobs are at risk across all levels of the business, owned by Dubai-based DP World.
It emerged in early April that P&O Ferries was seeking a £150 million bailout from the UK Government to avoid collapse, but no offer was made.
The PA news agency understands that the firm's proposal was based on running its full complement of 21 ships.
But the company is now only operating 15 vessels, with reduced frequency, and expects to reach an agreement with the Government for a lower amount of money to secure critical supply routes.