The Philippines’ ministry of labour migration has started an investigation into the exploitation of cleaners at four branches of the Saints & Stars luxury gym chain in Amsterdam.

According to a ministry spokesman, gym owner Tom Moos failed to request accreditation from the ministry in Manila or its European agency in Berlin before employing the workers.

The accreditation system is a way for the government to monitor where labour migrants from the Philippines are working and if their employment is legal. The accreditation is not a condition according to Dutch law.

The cleaners were forced to work up to 17 hours a day and share beds with strangers while cleaning the four branches of the luxury gym chain Saints & Stars in Amsterdam, the Parool reported three weeks ago.

At least 23 of the cleaners were made to surrender their passports while the company organised their visas and work permits, the paper said. Many were recruited directly in their home countries.

The labour inspectorate confirmed that 23 undocumented Philippine and Indonesian migrant workers were found during recent inspections at the Amsterdam gym chain.

Caretaker social affairs minister Eddy van Hijum said reports of the cleaners’ conditions were “unacceptable”. “These kinds of abuses don’t belong in the Netherlands, but they’re too often being reported by the labour inspectorate,” he said.

Eleven of the cleaners were invited to the Philippines’ embassy in The Hague, where they have been offered support. The embassy has also contacted the Dutch labour inspection, police and the Dutch immigration service IND.

They have also sought legal advice and are trying to obtain a temporary work permit for victims or witnesses of possible human trafficking.  Well-wishers have launched a crowdfunding campaign for the cleaners which has raised over €30,000 so far.

Owner Tom Moos denies he exploited the cleaners but offered the cleaners €3,000 each if they would sign a statement to say they had been treated well, which they refused.

Van Hijum said the case is “a serious one” and that labour inspectors are investigating whether the gym owner should be prosecuted.

He also said fines, currently at €11,250 for each individual case, are too low to be a deterrent and should be at least “a couple of thousand” higher, he told NPO financial programme Geld of je leven (Money or your life).