Union chiefs called on a ferry boss today to retract comments that labelled Britons as "quite fat and covered in tattoos".
Steve Todd, head of maritime at the RMT union, said Pim de Lange's remarks were an "appalling, abusive and derogatory" attack.
The director of Stena Line's North Sea routes, which operate between Harwich and the Hook of Holland, also said it was hard to find British workers who were young and fit for the job.
He later said his initial comments, made to a Dutch newspaper, were taken out of context.
And he added in a statement that he regretted any offence he had caused and apologised.
But Mr Todd said Mr de Lange had not gone far enough.
"It's an appalling, abusive and derogatory attack on British ship workers," he said.
"RMT is demanding a full retraction of all the statements he has made and a full apology to all British seafarers for his behaviour.
"These are people who have helped generate huge profits for Stena. We want it recognised that British seafarers are the best in the world.
"I think his comments subsequently have been wholly inadequate."
The row comes at a time when RMT, which represents rail, maritime and transport workers, is balloting for industrial action.
It follows claims that Stena Line, whose head office is in Sweden, was planning to hire Filipino workers on rates of £2.20 an hour.
Dutchman Mr de Lange insisted the company was committed to maintaining a mix of British, Dutch and Filipino employees.
"I regret any offence caused by my comments and apologise," he said.
"I hugely value the contribution of our British and Dutch employees, along with our Filipino crew, and as usual we will continue to work together.
"Our employee mix and pay scales on our new superferry, the Stena Britannica, will be the same as previously.
"Contrary to media coverage, we have not been on a recruitment drive in the Philippines and are not making any UK seafarers redundant, but instead will continue to employ a mix of British, Dutch and Filipino workers, as we have always done.
"At present, with the new Stena Hollandica sailing and the new Stena Britannica launching in October, our employment ratio of nationalities is very similar to previous years.
"On the new superferry we will employ more UK seafarers than on the present Stena Britannica.
"All oUr British and Dutch employees are hugely valued, as are our Filipino staff, who have an excellent reputation for hospitality services, which we and our customers value enormously."