UK prime minister Boris Johnson said it appears to him that P&O Ferries has “broken the law” over the controversial sacking of 800 workers.
He told the House of Commons that the UK government will be “taking action”, and encouraged workers to do the same.
His statement came as the company’s chief executive issued an apology for the impact of the decision to sack the staff without notice.
Peter Hebblethwaite said he understood the “anger and shock” about the loss of jobs.
His statement came amid continued protests by unions and workers and followed confirmation that he will appear before MPs on Thursday to be questioned about the dismissals.
He said: “I want to say sorry to the people affected and their families for the impact it’s had on them, and also to the 2,200 people who still work for P&O and will have been asked a lot of difficult questions about this.
“Over the last week, I’ve been speaking face-to-face to seafarers and their partners. They’ve lost their jobs and there is anger and shock and I completely understand.
“We needed fundamental change to make us viable. This was an incredibly difficult decision that we wrestled with but once we knew it was the only way to save the business, we had to act.
“All other routes led to the closure of P&O Ferries. I wish there was another way and I’m sorry.”