Canada's envoy to Beijing on Thursday threw cold water on long-sought free trade between the two nations as an ugly diplomat spat over Canada's detention of a top Chinese tech executive drags into a second month.

Ambassador John McCallum, who returned to Canada to brief lawmakers on the row, told reporters that Canadian businesses want to press on with growing the trade relationship.

But, he added, exploratory talks on free trade that started in September 2016 are now dead and unlikely to be revived in the forseeable future.

"We are certainly not negotiating free trade with China either before or after this. So it's not on the table right now," McCallum told reporters.

"Canada has invested a lot in China," he said. "Our tourist industry, our universities, our farmers are all highly dependent on China and I think China will still play a very important part in Canada's future."

Canadian businesses "want to continue moving forward in China," McCallum said.

But right now Ottawa is preoccupied with securing the release of two Canadians detained in China and obtaining clemency for a third on death row.

"Our top priority by a longshot is to get our two Canadians back and to save the life of the third. That is top of the list," the ambassador said.

Canada and China became embroiled in a tit-for-tat diplomatic row following the arrest in Vancouver of Huawei executive Meng Wanzhou on a US warrant.

Meng faces extradition on fraud charges for alleged Iran sanctions-busting and lying to US banks about it.

- "Hostage" diplomacy? -

In a move widely seen as a counterstroke, Chinese authorities arrested two Canadians -- former diplomat Michael Kovrig and businessman Michael Spavor -- accusing them of espionage.

Ottawa insisted they had been "arbitrarily" detained and that interrogations of Kovrig breached the Vienna Convention on diplomatic relations -- allegations Beijing flatly rejected.

Former Canadian justice minister Irwin Cotler went further, accusing China in an email to The Canadian Press of "hostage diplomacy."

Story continues

Canada and China have flirted with the idea of deepening trade ties since the 1990s.

During tense negotiations with the United States and Mexico to revamp a continental free trade agreement last year, growing trade with China was touted as a means of reducing Canada's heavy trade reliance on the United States.

This would have made Canada the first Western nation to reach a free trade deal with Beijing.

But when exploratory talks floundered, Ottawa instead joined the Trans Pacific Partnership. This move came on the heels of a Canada-EU free trade pact in 2017.

Canada still sends 75 percent of its exports to the United States. But since 2003, China has been its second largest trading partner.

According to the latest government data, Canada exported Can$2.1 billion (US$1.6 billion) in goods to China in November while importing Can$3.9 billion (US$3.0 billion) in goods from China.