A Canadian volunteer teacher remains in critical condition fighting for her life after a knife-wielding assailant slit her throat during a robbery attempt in Thailand.

Maya Lloyd, 22, from the University of Toronto, who had arrived in the country in late August, received a 10-centimetre-long cut on her throat that pierced her larynx.

She is on a life-support machine at Krabi Hospital's intensive care unit.

Thai Education official Jiraporn Chairit said Lloyd, a psychology major at the University of Toronto, came to the province of Krabi to work as a volunteer teacher at Nong Talae Wittaya School.

Jiraporn said she had accompanied Lloyd to the state-owned house on August 30 where the two were living, but had used a separate entrance.

"I heard a fight just five minutes after we parted. I screamed for help and saw her attacker climbing over a fence," Jiraporn said.

When police arrived at the scene they found a pair of glasses, a hat and fingerprints on the wall that they suspect may belong to the attacker.

The house is located next to a field that drug addicts frequent at night, local residents said. Drug addicts often sneaked into the house where Lloyd was attacked, and in a recent burglary thieves made off with about Bt200,000 (C$7,300) in cash and valuables, one local resident said.

"No one has been arrested though," said the resident, who spoke to the local paper.

Education officials and teachers have taken turns visiting Lloyd.

Sudwarang Cherngdee, an English teacher who worked with the volunteer, described her as outgoing, open and helpful. "During the three days we worked together, I found her to be kind and devoted to her job," Sudwarang said.