Chinese-Australian writer Yang Hengjun, who disappeared at the weekend in China, is being held under “residential surveillance”, according to Australia’s defence minister Christopher Pyne.

Residential surveillance is a form of secret detention often used against Chinese activists that could mean months without access to a lawyer or contact with family. Pyne, speaking in Beijing on Thursday, confirmed Yang was being held by Chinese authorities.

“He is being held in residential surveillance,” said Pyne. “We would describe it as home detention. As Mr Yang doesn’t have a home in Beijing, he is being held in a similar situation, as opposed to being held in a prison.” Pyne said Yang was likely being held in Beijing.

“The Australian government is obviously concerned with the residential surveillance of Mr Yang. He is an Australian citizen, and we are seeking to provide him with consular assistance and support to ensure he is being treated fairly and transparently.”

At a press briefing on Thursday, China’s foreign ministry said Yang had been detained on “suspicion of endangering national security”. Spokeswoman Hua Chunying said Yang’s rights and interests were being protected in accordance with Chinese law.

The form of detention Yang is under is known as “residential surveillance at a designated location”, or RSDL.

“RSDL is so concerning precisely because it institutionalises enforced disappearances and raises the risk of torture, both gross human rights violations and crimes under international law,” said Michael Castor, a human rights advocate focusing on RSDL.

“This likely means Yang Hengjun may face up to six months of secret detention, denied any access to a lawyer, no contact with his family, and at high risk of abuse, and quite likely a forced confession at the end.”

Pyne said Yang had not been allowed consular access and he was unaware whether Yang’s family had been able to communicate him. Pyne said he would press for access to Yang at meeting with his counterpart in Beijing, the minister of national defence, General Wei Fenghe, later on Thursday.

Yang, a novelist and former diplomat, is one of China’s most prolific commentators. He obtained a PhD at the University of Technology Sydney and became an Australian citizen in the early 2000s. Yang, who lives in New York where he is a visiting scholar at Columbia University, was detained on 19 January after a flight from New York to Guangzhou. Yang was travelling with his wife and son.

His detention could escalate into another diplomatic incident between China and an ally of the US. Two Canadians, Michael Kovrig and Michael Spavor, were detained in China last month, widely seen as retaliation for the arrest of a senior executive at Chinese telecom giant Huawei in Canada at the request of the US.

Australia recently expressed concern about China’s detention of two Canadians in retaliation for the arrest in Canada of a senior Huawei executive.

Australia’s foreign minister, Marise Payne, said on Thursday that there is no connection between the detention of Yang and the cases of two Canadians in custody.

Australian embassy officials in Beijing had an initial meeting with Chinese authorities on Thursday. Payne expressed concerns about the nature of the novelist and influential online commentator’s detention.

“We have requested, and we do expect, consular access at the earliest possible opportunity,” Payne told reporters in Sydney.

Asked if there were a connection between Yang and the Canadian cases, Payne responded: “At this stage there is no evidence of such a connection … I’d be concerned if there was an indication of that.”

“We are calling on the Chinese authorities to ensure this matter is dealt with transparently and fairly,” she said.

Payne doesn’t believe Yang’s detention is related to an Australian government decision to shut Chinese telecommunications giants Huawei and ZTE out of Australia’s 5G network.

“I think if there were concerns to be raised, they would have been before now,” she said.

Yang’s friend, University of Technology Sydney academic Feng Chongyi, said the writer’s detention was much more serious this time compared with when he was detained in 2011 because of Beijing’s current trend of “hostage diplomacy”.

“ [The Australian government] should be very, very firm on this because the Chinese government is behaving like terrorists,” he told the Guardian.

Feng has been told Yang could be facing espionage charges in Beijing and he himself has also been previously detained in China.

Consular agreements between the two countries stipulate that either government must be informed within three days if a citizen is detained and consular access should be granted soon after.

Pyne said Chinese officials had taken four days to notify Australia about Yang’s detention. “Obviously that is disappointing,” he said.

The opposition leader, Bill Shorten, said he hoped there will be a breakthrough soon.

“It’s been a slow response from the Chinese government to talk to the Australian government,” Shorten told ABC TV. “This is not the way which relations between our two countries should be conducted at all.”

Former prime minister Kevin Rudd, who speaks Mandarin, tweeted support for Yang. “Yang Hengjun is an Aus citizen just like the rest of us with equal rights and protections,” Rudd said.

“China has an international legal obligation under [article] 12 of our 1999 treaty for full consular access & to advise what Chinese law he is alleged to have breached.”

PEN America, an organisation that supports writers and freedom of expression, said Yang’s detention is “a terrifying sign of the Chinese government’s willingness to disappear writers who criticise them, regardless of nationality.”

“It’s obvious that Yang would not have been seized if it weren’t for his previous critical writings,” spokeswoman Summer Lopez said.

Yang’s novel Fatal Weakness, part of a trilogy, explores espionage between China and the US, a topic he has also written about on his blog. Yang has a large Twitter following and frequently writes about issues involving China’s government.

He is not known for outright criticism of the party, and his most recent tweets and posts have focused on US politics, his health, or books he has read. In December, he tweeted an earlier blog post he had written in 2011: “I have confidence in the future, but without today’s efforts and sacrifices, the future may never come. For people like me, the goal is for that bright future to arrive sooner.”