SINGAPORE - An Irish woman who worked in Singapore as a physiotherapist has been declared brain dead after she collapsed during a trekking holiday to Indonesia.

The family of 22-year-old Lisa Orsi said on Friday that her organs will be donated in accordance with her wishes. She was officially declared brain dead on Thursday.

Her father Dennis said: "She would really want as many of her organs used to help as many people as possible.

"She was very determined that if anything bad ever happened, organ donation would be very high up the list. But we didn't realise it would happen before she was 23."

Ms Orsi was on a four-day trip to Indonesia with a group of friends. She lost consciousness after hiking up a volcano, and was first warded in a hospital in Surabaya.

She was diagnosed as having suffered severe brain damage from hypoxia - or a lack of oxygen - and moved to Singapore General Hospital on Feb 25.

"I realised the situation was very bleak and that things were not going to improve," said Mr Orsi, 46.

He added that Ms Orsi was put on mechanical ventilation as she could not breathe on her own. She did not regain consciousness.

Her father painted a picture of an active, independent young woman who was very close to her family.

"She had a massive appetite for seeing things and travelling," he recalled.

Ms Orsi had travelled widely - from Italy to India. But despite her busy lifestyle, she would make time to call her family back home in Northern Ireland three times a week.

Early last year, she came to Singapore and started work in Bright Vision Hospital as a physiotherapist.

Her plan was to save up some money and read medicine at Edinburgh University after she completed a two-year stint here.

Friends, family and hospital staff have been extremely supportive, said Mr Orsi.

"It's been so overwhelming. There have been hundreds of people."

The organ donation process began at SGH on Friday. When this is complete, Ms Orsi's body will be flown home for burial.