They were contracted by McDermott and employed by DOF Subsea.
Today a spokesperson from the National Offshore Petroleum Safety and Environmental Management Authority (NOPSEMA) confirmed earlier reports it was facing a lawsuit to Energy News, but said further detail cannot be given as the matter is "before the courts."
In a report yesterday, The Sunday Times revealed NOPSEMA had been added as a defendant to a suit brought by the divers, alongside Inpex and McDermott and DOF Subsea Australia.
Kakulas Legal injury lawyers are representing the divers and the matter is being heard in the District Court of Western Australia.
The operations were undertaken based from the Skandi Singapore dive support vessel in June and July 2017.
The divers spent up to 27 days in the pressurised environment as they repaired a pipeline for Inpex, 273 metres underwater, the deepest commercial operation in Australian history.
Sources have claimed the complaints arose from an expedited process of "blow down" - which involves a chamber in which they are living in being pressurised with a mixture of helium and oxygen close to that of the expected working depth outside the chamber.
The divers claim they have been suffering severe decompression sickness, including neurological symptoms such as hallucinations, nausea, headaches, tremors and cognitive impairment that have lasted an unusually long time and left them unable to work since 2017.
The dive is subject to a lengthy investigation by NOPSEMA, with contractor DOF Subsea pledging to assist the regulator to investigate at the time.
In April 2018, DOF Subsea said "the diving operations were conducted in accordance with our NOPSEMA-accepted diving operations manual and recognised industry standards".
A DOF Subsea Australia spokesperson told Energy News this morning they were unable to comment until NOPSEMA's investigation had concluded.
"DOF Subsea regards the ongoing safety, health and well-being of all its employees and contractors as being of paramount importance," they said.
Separately, NOPSEMA released a draft revision of diving guidelines for comment on Thursday, noting it had identified a number of issues during the drafting process that would benefit from further industry discussion.
A NOPSEMA spokesman told Energy News the release of draft revisions is part of a rolling process that it works through to review all guidelines it issues to industry, to ensure they remain fit for purpose.
He said NOPSEMA is aware of the legal action referenced by media, but would not provide further comment on it while it remained before the courts.
An Inpex Australia spokesperson told Energy News they were currently not in receipt of a writ.
McDermott could not be reached for comment.