Australia’s spy chief has revealed that critical infrastructure, including the electricity grid and water supplies, could not have been adequately protected if China's Huawei or ZTE had been allowed to build the country's new 5G mobile networks.

In the strongest comments by a government official since the ban was handed down on Chinese companies in August, Mike Burgess, the director-general of the Australian Signals Directorate, said the stakes in 5G "could not be higher".

"Getting security right for our critical infrastructure is paramount," he said.

The warnings coincide with a report by the Australian Strategic Policy Institute that reveals Australian universities are collaborating with Chinese military scientists at unprecedented levels while failing to mitigate against the risk that such co-operation might harm national security.