Foreign Minister Marise Payne has issued a statement raising concerns about China's detention of two Canadian citizens, after foreign policy experts questioned why the Federal Government had been keeping quiet about it.

Key points: Canada says the pair are caught up in a diplomatic row and has called for their release

Canada says the pair are caught up in a diplomatic row and has called for their release The country's major Western allies have made similar public statements, but Australia had not — until now

The country's major Western allies have made similar public statements, but Australia had not — until now Foreign Minister Marise Payne has outlined her support of Canada's justice system and her approach to the issue

The detention of entrepreneur Michael Spavor and former diplomat Michael Kovrig earlier this month came shortly after Canada arrested a Huawei executive in Vancouver at the request of the United States.

Canada has called for the pair — accused by China of endangering state security — to be released, suggesting they have been caught up in an escalating diplomatic row.

Canada's major Western allies made similar public statements, but Australia had not.

"It's difficult to understand why the Australian Government has been so silent on this fundamental issue of democratic values," said the head of the National Security College at the Australian National University, Rory Medcalf.

He is one of 30 scholars, former diplomats and researchers who have signed a petition asking Senator Payne to back Canada's call for the pair to be immediately released.

"We ask the Australian Government without further delay to support Canada's call for the immediate release of these two detainees," the petition reads.

"The European Union, United States, United Kingdom, Germany and France have each issued statements of concern regarding the apparently political motivation for the arrests of these Canadian citizens, which raise serious concerns about legitimate research and business practices in China.

"It is time for Australia to do the same."

Following the release of the petition, Senator Payne released a brief statement supporting Canada's justice system and outlining her approach to the issue.

"The Australian Government is concerned about the recent detention of two Canadian citizens in China," she said.

"We would be very concerned if these cases were related to legal proceedings currently underway in Canada involving a Chinese citizen, Ms Meng Wanzhou.

"The Australian Government has conveyed this position to Chinese counterparts and we have been in regular contact with Canadian officials."

But Senator Payne's statement does not go as far as backing Canada's call for the two men to be immediately released, which is what the scholars' petition calls for.

Federal Labor on Monday supported Canada's call for the pair to be freed, saying it was "deeply concerned" about their ongoing detention.

"I think it's very important … when there are ally countries like Canada expressing concerns about the rights of their citizens that we are prepared to raise those concerns directly with China," Deputy Opposition Leader Tanya Plibersek said.

Canada, US call for China to release both men

Speaking just before Christmas, Canadian Prime Minister Justin Trudeau made an appeal for the release of Mr Spavor and Mr Kovrig, blaming their detention on tense US-China relations.

"This is one of the situations you get in when the two largest economies in the world, China and the United States, start picking a fight with each other," he said.

"The escalating trade war between them is going to have all sorts of unintended consequences."

Canadian Prime Minister Justin Trudeau said the US-China trade war will have "unintended consequences". ( Reuters: Ruben Sprich )

US Secretary of State Mike Pompeo likewise called for China to release both men.

"The unlawful detention of two Canadian citizens is unacceptable. They ought to be returned."

Mr Medcalf and the other foreign policy experts who have signed the petition want to see Senator Payne express similar sentiments.

"I think the increased frustration of this group of scholars is that the quiet approach isn't working," he said.

"If middle-sized democracies don't stand together against offensive behaviour by China on the international stage, then one by one we'll be subjected to similar punishment or bullying on those occasions when our interests clash with China's."

Australia 'at odds with other liberal democracies'

ANU visiting fellow Adam Ni is going to China next month as part of his regular travels to the country.

He signed the petition, arguing it is short-sighted of Australia not to publicly support Canada in this case.

"It really puts Australia at odds with other liberal democracies on this issue," he said.

"If moral suasion is not enough, then I think the Australian Government should really look at our national interest to ensure that when something like this happens to Australian nationals, then like-minded countries would likewise support our protests against the Chinese Government.

"Researchers like me, we travel to China frequently in order to do research.

"Under other circumstances, if there was trouble in Australian-China relations, then it is people like me … that might be harassed by the Chinese Government or potentially even detained."