Comcare has started monitoring the mould situation at the Nauru detention centre following reports staff and asylum seekers have become sick from exposure.
The federal work health and safety watchdog has been criticised for dragging its heels on addressing a mould scandal at the Nauru immigration detention centre.
At least 20 former detention centre staff have become seriously ill from mould exposure, including an Australian teacher who now has a cognitive disability.
Comcare started "monitoring compliance activity" at the Nauru detention centre on February 12 and is "examining a number of allegations concerning unsafe conditions caused by mould", according to leaked emails obtained by AAP.
The move came days after AAP revealed mould and construction problems at Nauru and Manus Island detention centres.
Australian Lawyers Alliance spokesman Greg Barns said Comcare was late to the party.
His organisation had been pushing the agency to exercise its powers on Nauru since June 2016 after releasing a report raising concerns the Commonwealth was failing in its duty of care.
"It's too little too late," Mr Barns told AAP.
"If this was Parliament House, Canberra, with a mould problem, you wouldn't have to rely on media stories to get it fixed."
He said the agency should be investigating the matter formally and considering criminal and civil charges.
A top-secret report from December 2014 warned Australia's immigration department (now Home Affairs) and then-detention centre operator Transfield (now Broadspectrum) of mould health risks.
Comcare has previously admitted it received a complaint in 2016 from a worker employed by a contractor, who had been diagnosed with a respiratory condition after living at the Nauru detention centre.
However, the agency said last month it was satisfied that reasonably practicable steps were taken to address problems with mould at the centre, and that the most recent site inspection in August 2017 found no significant issues.
Further comment has been sought from Comcare.
Last week, it emerged the Home Affairs department wasted $50,000 of taxpayer money on an industrial steam cleaner, but the machine was too dangerous to use and not appropriate for cleaning tents.