CANBERRA, Australia — Australia on Thursday urged China to treat a Chinese-Australian writer fairly and transparently almost a week after he was detained in what a friend suspects is part of a backlash against Canada's arrest of a top Chinese telecommunications executive.

Spy novelist and online commentator Yang Hengjun was a Chinese diplomat before he became an Australian citizen. Friends say the 53-year-old had been living in New York as a visiting scholar at Columbia University and had returned to China last week with his wife, Yuan Rui Juan, and 14-year-old stepdaughter.

Foreign Minister Marise Payne said Chinese authorities notified the Australian Embassy in Beijing on Wednesday night that they had detained Yang.

"We will continue to make representations to China to ensure that this matter is dealt with transparently and fairly," Payne said in a statement.

"Our embassy in Beijing will meet with Chinese authorities this morning to seek further clarification of the nature of this detention and to arrange consular access at the earliest possible opportunity, in accordance with the bilateral consular agreement," she added.

Opposition leader Bill Shorten, whom opinion polls suggest will become prime minister at general election due by May, criticized China for failing to notify Australia within three days that an Australian had been detained, as stipulated by the consular agreement.

"It's surprising and concerning," Shorten told reporters.

Yang's friend, University of Technology Sydney academic Feng Chongyi, said he believes Yang is being detained in Beijing by the Ministry of State Security on suspicion of espionage.

The detention comes a month after China's detention of two Canadians, entrepreneur Michael Spavor and former diplomat Michael Kovrig, in what was widely seen as retaliation for Canada's arrest of Huawei Chief Financial Officer Meng Wanzhou at the request of the United States.

Feng, who has been in contact with Yang's family and friends, said Yang's detention was "directly linked to the Huawei case."

Feng said he had warned Yang against traveling to China in light of the Canadians' arrest. Yang had argued that he was safe because he had flown to China several times since taking the university job in New York in 2016.

"I told him the situation had changed. He didn't believe me. It was a horrible misjudgment," Feng said.

Feng was detained in China in 2017 near the end of a three-week trip during which he was researching human rights lawyers, and he was questioned by security services for two weeks before he was allowed to return to Australia. He said on his return to Sydney that he was unable to discuss the details of his experience.

Rory Medcalf, head of the Australian National University's National Security College, had warned after the Canadians were detained that an Australian could be the next victim of "China's hostage-taking."

"It's hard to tell the precise reason for this detention," Medcalf said. "I think rather it's a signal that we're now — not only Australia, but really all democracies, all middle powers — are in for a period of sustained tension with China where the safety of our nationals in China simply cannot be assured."

Yang's detention comes ahead of a visit by Defense Minister Christopher Pyne to China on Thursday. Pyne left Australia on Tuesday for a weeklong visit to Japan, then China and Singapore.

Columbia University said Yang had been a visiting scholar with the School of International Public Affairs' Institute for the Study of Human Rights since 2016. Spokeswoman Caroline Adelman said the university had no comment on Yang's detention.