Some 600 people who use Philips equipment to deal with their sleep apnea are going to court in the Netherlands to get the government to release confidential documents about the apparatus.

The case centres on 1,000 documents detailing the results of research and correspondence between Philips and the health ministry about problems with the equipment, the NRC reported on Friday.

Research by the paper has shown that problems with the foam used in the breathing machines were known about in 2016 but Philips did not go public with the issue until last year.

‘We want to know what the health ministry knew about the problems and, most of all, when,’ lawyer Mark de Hek told the paper.

Philips has recalled 5.5 million machines and 17 million sleep masks worldwide after it emerged that tiny foam particles could be released during cleaning and then inhaled, while magnetic clips in the masks potentially interfere with heart pacemakers.

The replacement of the Philips Respironics ventilators has cost the company an estimated €900 million and driven down its share price by more than 60% in the last 18 months.