Canada will join the United States in seeking to uphold the rules-based international order after the saga over Chinese tech giant Huawei has pushed relations between Ottawa and Beijing to “a turning point”, a former Canadian ambassador to China says.

David Mulroney, Canada’s envoy to China from 2009 to 2012, made the comment amid deteriorating relations between the two countries since December, when Huawei executive Sabrina Meng Wanzhou was arrested in Vancouver at the request of the US over an alleged breach of sanctions on Iran.

China has since detained two Canadians on espionage charges, sentenced another two Canadians to death and blocked imports of pork and canola from the country.

“The resulting Canada-China crisis is simply one of a series of disputes – erupting in many places around the world – that are at heart about China’s obvious disdain for a rules-based international order,” said Mulroney, who is now a distinguished senior fellow at the University of Toronto’s Munk School of Global Affairs.

“We are coming to the end of a long period during which China has been allowed to be a free rider, reaching a point at which it is a growing threat to the rules-based international order that Canada helped to create,” he said, adding that Ottawa had a real stake in speaking out on behalf of the system.

According to Mulroney, the rift had pushed Ottawa to seek closer ties with Washington, Beijing’s biggest geopolitical rival, and to take a more sceptical view of China’s initiatives that were “mainly designed to promote Beijing’s power and influence”.

“I think we have reached a turning point. Canada will almost certainly turn from an uncritical ‘comprehensive engagement’ to a much more carefully measured engagement that is better at balancing risks and opportunities,” he said.

In Washington on Thursday, Canadian Prime Minister Justin Trudeau told US President Donald Trump that he expected the plight of two Canadians detained in China – former diplomat Michael Kovrig and businessman Michael Spavor – to be raised when Trump meets Chinese President Xi Jinping at the Group of 20 summit in Japan next week. The US president gave him assurances that he would do “anything” to help Canada in its row with China.

As a Group of Seven leading industrialised nation, Canada has also questioned the transparency and intentions behind China’s global trade and infrastructure strategy the Belt and Road Initiative, although Italy, another G7 member, signed up for the scheme in April.

On the biggest challenges facing bilateral relations between Canada and China, Mulroney said he was most concerned about the extent to which Beijing used coercion – such as extralegal detentions and economic blackmail – to isolate and dominate other countries.

“China won’t like it much [the criticism], but it’s just about the only truly effective tool in the toolbox,” said Mulroney, who also criticised Beijing for exploiting open markets abroad while keeping its own market closed.

The world’s second largest economy, China is now the biggest trading partner for many nations and has been criticised for using economic sanctions as a tool against them when bilateral ties turn sour.

Since Huawei chief financial officer Meng was arrested, China has placed a number of hurdles in the way of Canadian trade, banning imports from two canola producers, holding up pork shipments over paperwork issues, and using unusual obstacles to halt soybean and pea exports.

On Tuesday, Chinese state news agency Xinhua said the country would stop imports from Canadian firm Frigo Royal over food safety issues. It said traces of ractopamine – a feed additive banned in many countries including China but not in the US and Canada – were found in a shipment of pork. Frigo Royal is the third Canadian pork company to have its imports blocked by China, after it halted shipments from Olymel and Drummond Export in April over labelling issues.