Australia has been targeted by a cyber attack that is threatening all levels of government, businesses, essential services and critical infrastructure, the prime minister has said.

Prime Minister Scott Morrison would not name the state, amid inevitable speculation that the cyber attacks were part of Australia’s increasingly hostile rift with China.

Morrison said he made the growing threat public to raise awareness and particularly wanted organisations involved in health, critical infrastructure and essential services to bolster technical defences.

A range of sectors were being targeted and the frequency of cyber intrusions to steal and cause harm has increased for months, he said.

“This is the actions of a state-based actor with significant capabilities. There aren’t too many state-based actors who have those capabilities,” Morrison said, without naming a specific country.

Monash University international security expert Greg Barton said the malicious nature of much of the reported cyber crimes suggested it was part of deteriorating relations between China and Australia.

“There’s no doubt that it’s China,” Barton said. “It might be a bit of rattling of the cage and reminding us that we have some vulnerabilities and we could end up with some heavy costs that we really don’t want to think about.”

China in recent weeks banned beef exports from Australia’s largest abattoirs, ended trade in Australian barley with a tariff wall and warned its citizens against visiting Australia. The measures are widely interpreted as punishment for Australia’s advocacy of an independent probe into the origins and spread of the coronavirus pandemic.

Australia’s foreign minister this week accused China of using the anxiety around the pandemic to undermine Western democracies by spreading disinformation online, prompting China to accuse Australia of disinformation.

Morrison said “Australia doesn’t engage lightly in public attribution”, but said he couldn’t control speculation about who was responsible for the cyber campaign.

He offered few details about the activities and said it was difficult to understand whether the intrusions were motivated by desires to steal state secrets, intellectual property or the personal data of ordinary Australians.

Australian investigations to date had not uncovered any “large-scale personal data breaches,” Morrison said. And he said many of the intrusions had been thwarted.