An Irish physiotherapist who died after collapsing during a hiking trip to Indonesia may not have had an adequate supply of oxygen to her brain or received timely medical care, an investigation has found.

Ms Lisa Orsi, 22 - who worked at Bright Vision Hospital in Singapore - had been on a trekking trip with friends on Mount Bromo in East Java when she was found lying in the shower of a hostel 2,300m above sea level.

Investigation officer Chia Hong Kai said in his investigation report at an inquest yesterday that Ms Orsi had flown to Surabaya on the evening of Feb 18 and met her five friends at the airport.

She was observed to be unwell during the ride up to the hostel.

After a few hours' sleep, the group travelled by jeep to Kingkong Hill, one of Mount Bromo's viewing points.

After about an hour, they headed down to the volcanic crater, where they rode horses.

Back at the hostel, Ms Orsi was seen blowing her nose a lot and hard. She also complained about having earache and feeling tired.

The group took a short walk outside and, on their way back, Ms Orsi's face was flushed and she was panting. Her ear was still painful and she had stomach cramps.

She also complained that her room was too cold. Her roommate noticed that she was making some odd breathing noises.

The next morning, on Feb 20, she was found lying face up in the shower, and could hardly open her eyes.

She was taken to a clinic, then to a hospital before being transferred to Surabaya's Siloam Hospital for neurological treatment - some seven hours after collapsing. Along the way, she vomited twice.

A doctor at the hospital found that her brain had swelled, and she had fallen unconscious.

She was moved to Singapore General Hospital on Feb 25. On admission, she was put on mechanical ventilation.

Dr John Ng, an associate consultant at the Department of Neurology, assessed that Ms Orsi was likely suffering from high-altitude cerebral oedema - an accumulation of fluid and resultant swelling to the brain.

After certifying her brain dead on March 4, approval was obtained to harvest her organs, according to her wishes. This was done two days later.

The final cause of death was given as hypoxic ischaemic encephalopathy caused by lack of oxygen to the brain.

State Coroner Marvin Bay will give his findings on Sept 22.