Canada bans Huawei equipment from 5G networks and orders removal of all equipment by 2024, drawing condemnation from China.
Beijing has lashed out at Canada for banning two Chinese telecoms giants from Canadian 5G networks.
Chinese authorities on Friday called Ottawa's security concerns "groundless", while Huawei said barring its services was a "political decision".
Canada's long-awaited measure on Thursday follows the United States and other key allies, and comes on the heels of a diplomatic row between Ottawa and Beijing over the detention of a senior Huawei executive on a US warrant, which has now been resolved.
The United States has warned of the security implications of giving Chinese tech companies access to telecommunications infrastructure that could be used for state espionage.
Along with Huawei, Chinese telecoms firm ZTE was also banned.
Both Huawei and Beijing have rejected the US security allegations.
"China is firmly opposed to this and will conduct a comprehensive and serious assessment," Foreign Ministry spokesperson Wang Wenbin told reporters in response to the 5G block.
"The Canadian side has excluded these Chinese companies from the Canadian market under the pretext of groundless security risks and without any solid evidence."
Move contrary to free-trade rules
He added that Beijing would "take all necessary measures" to protect Chinese companies.
"This move runs counter to market economy principles and free trade rules," he said, accusing the Canadian government of "seriously damaging the legitimate rights and interests of Chinese companies."
Huawei called the ban "an unfortunate political decision" that cannot be justified on national security grounds.
"Huawei Canada is disappointed by the Canadian government's decision," the company's Canadian subsidiary said in an email to AFP. "This is an unfortunate political decision that has nothing to do with cyber security or any of the technologies in question."
It said that Huawei hardware and software has been "routinely and closely scrutinised" by the Canadian government and its security agencies, and to date there have been "zero security incidents caused by Huawei equipment".
Canada had been reviewing the 5G technology and network access for several years, repeatedly delaying a decision that was first expected in 2019.
Canadian Industry Minister Francois-Philippe Champagne made the 5G announcement on Thursday, citing the "intention to prohibit the inclusion of Huawei and ZTE products and services in Canada's telecommunication systems".
Champagne said Canadian telecommunications companies "will not be permitted to include in their networks products or services that put our national security at risk".
"Providers who already have this equipment installed will be required to cease its use and remove it," he said.
Huawei already supplies some Canadian telecommunications firms with 4G equipment.
Most, if not all, had held off using Huawei in their fifth-generation (5G) wireless networks that deliver speedier online connections with greater data capacity. Others have looked to other suppliers while Ottawa hemmed and hawed.
Canadian Public Safety Minister Marco Mendicino warned on Thursday of "many hostile actors who are ready to exploit vulnerabilities" in telecom networks.
The United States, Australia, Britain, New Zealand, Japan and Sweden have already blocked or restricted the use of Huawei technology in their 5G networks.