The owners of cruise ship Oasis of the Seas are facing thousands of euros in fines for violations of Dutch employment law, the social affairs and employment inspection agency SZW said on Monday evening.

The vessel, the world’s largest cruise ship, is currently moored at the Keppel Verolme dockyard in the Botlek area of Rotterdam where it is undergoing two weeks of intensive renovation work, including the placement of a new engine.

The ministry says hundreds of workers were flown in to Rotterdam to cope with the amount of work and many of them do not have a work permit or are being underpaid. The agency also suspects that working time limits are being violated.

The Oasis of the Seas is owned by Royal Caribbean Cruises and arrived in Rotterdam on September 30 carrying 5,400 passengers and 1,500 crew.

According to the AD, the fines focus on 48 Filipino workers who do not have permits. The fine is a maximum €12,000 per worker, which means the cruise company faces a €600,000 bill, the AD says.