US Senators stepped up calls for Canada to steer clear of 5G network equipment supplied by Huawei, after the country’s head of cyber security said a ban on the vendor is not necessary.

In a letter to Canadian Prime Minister Justin Trudeau, Senators Marco Rubio and Mark Warner expressed “grave concerns” Canadian network security safeguards are “inadequate”. This, they argued, could ultimately compromise both Canada’s national security and cooperation between the country and other members of the Five Eyes intelligence sharing coalition.

Two members of the group – the US and Australia – have already taken steps to push Huawei out of their markets.

Rubio and Warner noted US and Canadian operators jointly benefit from “economies of scale for equipment designed for regionally harmonised frequencies.” However, they warned using Huawei kit for 5G could “seriously jeopardise this dynamic, depriving both Canadian and American operators of the scale needed to rapidly build out 5G networks”.

Both Rubio and Warner sit on the Senate Intelligence Committee, which oversees government intelligence activities and programmes.

The letter reiterates claims by US officials that Huawei has ties to the Chinese government and thus presents a national security risk.

Huawei adamantly denied these assertions, and recently argued to the US Federal Communications Commission its absence from the market will harm competition, increase prices and hinder 5G deployments.