SYDNEY — An Australian man has been freed after spending 36 hours trapped in a drain network.

He first entered a drain in Brisbane on Saturday "while trying to retrieve his phone", according to authorities.

The man, aged in his 30s, was rescued on Monday after emergency crews received a call about someone "stuck" underground.

He is now being treated for abrasions and hypothermia in hospital, officials said.

Local media reported he had waded through stormwater searching for an exit before eventually being rescued by firefighters who lifted a drain lid, allowing him to climb out.

The rescue effort took about five minutes, a Queensland Fire and Emergency Services spokesperson told the BBC.

Local resident James Lingwood — who made the call to authorities — told the Courier Mail newspaper that he first encountered the man on Sunday after hearing a voice "sort of yelling".

Lingwood said he looked into the drain and saw the man standing there, knee deep in water, and offered to help — but that his offer was declined.

"He seemed to be okay, and he said he could get out where he got in so I just left him alone," he told the Courier Mail.

But when passing the same drain on Monday, Lingwood said he decided to act after hearing "heavy breathing" indicating "someone was in distress".

The local council has previously posted warnings telling residents to "always stay away from storm water drains, pipes and manholes", describing them as a series of "grates and pits" which could easily "trap someone".

Floating debris and "poisonous substances" are listed as other potential dangers lurking in the waters.

It is unclear whether the man successfully retrieved his device. — BBC