An 18-year-old Saudi woman who fled her family saying she feared for her life has been granted asylum in Canada, Prime Minister Justin Trudeau said, as Thai officials confirmed the teen was en route to Toronto.

Key points: Rahaf Alqunun arrived in Bangkok a week ago and was initially denied entry

Rahaf Alqunun arrived in Bangkok a week ago and was initially denied entry Her resettlement in Canada came as a surprise to Australian officials, who were processing her application

Her resettlement in Canada came as a surprise to Australian officials, who were processing her application But there were growing fears over her security as she remained in Bangkok, so she was taken to the Canadian embassy

Mr Trudeau said the United Nations High Commissioner for Refugees (UNHCR) had asked Canada to take in Rahaf Mohammed Alqunun, who grabbed international attention this week after she barricaded herself in a Bangkok airport hotel room to resist being sent home to her family, which denies any abuse.

"Canada is a country that understands how important it is to stand up for human rights, to stand up for women's rights around the world, and I can confirm that we have accepted the UN's request," he told reporters.

The decision is likely to exacerbate Canada's already poor relations with Saudi Arabia, which last year barred the Canadian ambassador to Riyadh after Ottawa criticised Saudi authorities for detaining women's rights activists.

A Korean Air flight carrying Ms Alqunun left Bangkok at 11:37pm (local time), a Thai airport official said.

Loading

Thailand's immigration chief Surachate Hakparn told reporters it was Ms Alqunun's wish to go to Canada.

"She still refuses to meet with her father and brother, and they are going to be travelling back [on Saturday] as well … they are disappointed," he said.

Rahaf Alqunun prepares to leave Thailand for Canada. ( AP: Sakchai Lalit )

Ms Alqunun arrived in Bangkok on her way to Australia after fleeing her family in Kuwait, saying she had renounced Islam and that her family would kill her if she returned home.

Within hours a campaign dubbed #SaveRahaf spread on Twitter by a loose network of activists.

Following a tense 48-hour stand-off at Bangkok airport, some of it barricaded in a transit lounge hotel room, she was allowed to enter the country and was processed as a refugee by the United Nations Refugee Agency.

Ms Alqunun has accused her family of abuse, and refused to meet her father and brother who arrived in Bangkok to try take her back to Saudi Arabia.

Her case has drawn global attention to Saudi Arabia's strict social rules, including a requirement that women have the permission of a male "guardian" to travel, which rights groups say can trap women and girls as prisoners of abusive families.

Mr Trudeau brushed off a question as to whether Canada's move might make it harder to repair ties with Saudi Arabia.

"Canada has been unequivocal that we will always stand up for human rights and women's rights around the world," he said.

Rahaf Alqunun was placed under the protection of the United Nations in Bangkok. ( AP: Immigration police )

Australia said on Wednesday that it was considering taking in Ms Alqunun, and her resettlement in Canada came as a surprise to Australian officials.

Australia had been processing the application of the young refugee.

Ms Alqunun went to the Australian embassy in Bangkok on Wednesday and completed the visa application.

But Australian officials confirmed to the ABC that her case was still being processed as of late Friday.

There was growing concern within the UNHCR over Ms Alqunun's security as she remained in Bangkok.

With these security fears in mind, she was taken to the Canadian embassy in Bangkok on Friday morning. Her visa was processed within several hours and she was booked on a flight to Canada in the afternoon.

Australian Government accused of dragging its feet

Ms Alqunun, while being overjoyed at being safe and heading to a third country, had still hoped to come to Australia where her close friends are.

Immigration Minister David Coleman said Australia welcomed the news Ms Alqunun had been offered a place in Canada's humanitarian program.

"The safety of Ms Al-Qunun has always been the Australian Government's primary concern, and we have been working with the UNHCR and international partners to ensure her claim is assessed appropriately," he said in a statement.

"Australia has one of the most generous humanitarian programs in the world, and all applications are considered in accordance with Australian law and procedures."

But Greens Senator Sarah Hanson-Young accused the Government of dragging its feet.

"Canada showed Australia up — Justin Trudeau showed leadership, and showed up Scott Morrison," she said.

"He did what Scott Morrison and Australia should have done."

Ms Alqunun's Canadian settlement has emerged at a time when Riyadh is facing unusually intense scrutiny from its Western allies over the killing of journalist Jamal Khashoggi at the Saudi consulate in Istanbul in October, and over the humanitarian consequences of its war in Yemen.

ABC/Reuters