Thai immigration chief Surachate Hakpan said her father and brother would have to wait to learn whether the UN's refugee agency would allow them to.
"The father and brother want to go and talk to Rahaf but the UN will need to approve such talk," General Surachate told reporters.
The Australian government said on Tuesday it would consider the 18-year-old Saudi woman's desperate plea for asylum in a case that has drawn worldwide attention.
"The Australian Government is pleased that Ms Rahaf Mohammed Al-Qunun is having her claim for protection assessed by the UNHCR," a Department of Home Affairs spokesperson told SBS News.
"The government has made representations to the Thai Government and the Bangkok office of the UNHCR about its serious concerns on this matter and the need for Ms Al-Qunun’s claim to be assessed expeditiously," the spokesperson said.
"Any application by Ms Al-Qunun for a humanitarian visa will be carefully considered once the UNHCR process has concluded.
"Whether someone holds a visitor visa does not have a bearing on this process."
Earlier Tuesday, some of the 18-year-old Saudi woman's supporters said on social media her visa had been cancelled.
In response, the Australia director at Human Rights Watch, Elaine Pearson told the Guardian, "if the visa has been cancelled it would be very concerning".
"She's not safe in Thailand … I don’t think she'll be truly safe until she reaches a third country."
Ms Qunun was released into UN care on Tuesday evening, after a long stand-off with Thai immigration officials.
She had been holed up in a Bangkok hotel room, after being stopped by Saudi Arabian diplomatic staff who claimed she did not have the correct documentation.
Greens Senator Sarah Hanson-Young called on the Australian government to act "quickly" to ensure Ms Qunun's is ultimately granted asylum in Australia.
Ms Hanson-Young said Australia should offer "sanctuary" to Ms Qunan so she can live in a country that "respects women and girls".
Senator Hanson-Young's call comes after the Australian government revealed it had made representations to the Thai government on behalf of Ms Qunun, helping to ensure she is now able to access the refugee process under the care of UN officials.
"The claims made by Ms Alqunun that she may be harmed if returned to Saudi Arabia are deeply concerning," a Department of Foreign Affairs spokesman said.
Thailand is not a signatory to a UN convention on refugees, and asylum seekers are typically deported or wait years to be resettled in third countries.
The UNHCR insists anyone with an asylum claim should not be sent back to the country they fled under the principle of non-refoulement.
In a short press release distributed to media outside its embassy in Bangkok Tuesday, the Saudi government said it had not demanded her deportation, adding the case is a "family affair", but under the "care and attention" of the embassy.
In an earlier and separate explanation released on Twitter, the embassy also denied sending officials to Suvarnabhumi airport to meet Qunun as she arrived or impounding her passport -- as she alleged.
It also said the embassy had made contact with her father, a senior regional government official in the kingdom, "to inform him on her situation".
Thai immigration chief Surachate Hakparn told reporters that Qunun's father and brother had arrived in Thailand on Tuesday.
He said he would talk to the UN refugee agency about a potential meeting between the family members.
"Rahaf is not a political asylum case," he insisted. "It is not political at all."
He added that the Saudi government "agrees that there should be a priority on Rahaf's safety".
The immigration police released photos of Surachate and his team sitting down with Saudi embassy charge d'affaires Abdalelah Mohammed Alsheaiby.
Her father and brother are "the two male relatives (Qunun) most fears" and could "physically harm her in an effort to compel her to return", said Human Rights Watch's Phil Robertson, who has been in contact with her since she started live-tweeting her ordeal.
"She's an adult woman who has escaped Saudi Arabia's repressive and discriminatory 'guardianship' laws and these men must recognise the rules have changed," he said, adding it is "solely her decision" whether or not to meet them.
Qunun has said she believes she will be imprisoned or killed if sent back, and that her family is so strict they once locked her in a room for six months for cutting her hair.
A Change.org petition to grant Qunun asylum in Britain has so far garnered more than 80,000 signatures.
'I'm shouting out for help'
Ms Qunun had been bound for Australia to seek asylum, after fleeing her family in Saudi Arabia, saying she faced "real danger" - including death threats - if forced to return to her family under pressure from Saudi authorities.
She subsequently appealed for help from Australia, Canada, the United States, Britain and other European nations.
"Please I need u all. I'm shouting out for help of humanity," she tweeted.
Ms Qunun said she was being held at an airport hotel by diplomatic and airline staff, despite having a visa to travel to Australia.
Human Rights Watch provided SBS News with a document which appears to show Ms Qunun was granted a three-month visitor visa by the Australian Department of Home Affairs on 6 December 2018.
UN says assessment of claim will take five days
Late on Monday, she was allowed to enter Thailand temporarily under the protection of the UNHCR, which will take about five to seven days to study her claim for asylum.
"UNHCR consistently advocates that refugees and asylum seekers – having been confirmed or claimed to be in need of international protection – cannot be returned to their countries of origin according to the principle of non-refoulement," the UNHCR said in a statement.
Photos released on Monday night by immigration police showed Ms Alqunun with Thai and UN officials after she left the airport transit hotel room where she had been holed up over the weekend, sending her pleas for help on her Twitter account.
She later tweeted she feels safe under UN protection and has gotten back her passport, which had been taken from her earlier.
Labor's foreign affairs spokeswoman Penny Wong said she was concerned by the reports over the situation and had sought further information from the government.
"It is a very distressing position she is in," Senator Wong said.
Saudi woman seeking asylum in Australia pleads case
Immigration Minister David Coleman declined to comment.
Ms Alqunun said she had been abused by her family and would be killed if she returned home. She posted her passport details on Twitter to confirm her identity.
Saudi Arabian authorities have denied their involvement, saying Thai officials stopped Ms Alqunun because she did not have a return ticket or itinerary to show she was a tourist.
"She will be deported to the state of Kuwait where her family live," the Saudi embassy said in a statement.
"The embassy does not have the authority to stop her at the airport or anywhere else."
Fears for safety after renouncing Islam
Ms Qunun told a Thai human rights worker her family kept her in her room for six months because she cut her hair.
She had asserted her independence and renounced Islam but had been forced to pray, wear a hijab and was beaten by her brother.
Ms Qunun is understood to have fled from her family two days ago during a trip to Kuwait.
The incident comes as Saudi Arabia faces intense scrutiny over the shocking murder of journalist Jamal Khashoggi last year, which has renewed criticism of the kingdom's rights record.
- with AAP, AFP