Peter Dutton has promised “far right” and “far left” lunatics will be dealt with after the Australia’s spy chief warned about the growing threat of right-wing extremism.

Mr Dutton’s pledge came after ASIO boss Mike Burgess said right wing-extremists are regularly meeting in Australian suburbs to salute Nazi flags, inspect weapons, train in combat and share their hateful ideology – and emerging as one of Australia’s most challenging security threats,

In a rare public address from inside ASIO’s heavily fortified Canberra headquarters to deliver the organisation’s annual threat assessment, Mr Burgess said the extreme right wing had been in ASIO’s sights for some time. It came into sharp focus after the Christchurch terror attack last year.

On Tuesday, the Home Affairs Minister said an individual or organisation’s ideology was of no consequence to him or Australia’s security agencies.

“If somebody is going to cause harm to Australians, I just don’t care whether they’re on the far right, far left, somewhere in between, they will be dealt with,” Mr Dutton said.

“If the proliferation of information into the hands of right-wing lunatics or left-wing lunatics is leading to a threat in our country, then my responsibility is to make sure our agencies are dealing with it, and they are.”

Mr Burgess also revealed that ASIO had uncovered a sleeper agent running a major spy ring in Australia.

“The level of threat we face from foreign espionage and interference activities is currently unprecedented,” he said.

“It is higher now than it was at the height of the Cold War.”

New espionage and foreign interference laws were delivering dividends, with foreign intelligence services forced to change their tactics, he said.

“Wherever possible, ASIO seeks to ‘detect and protect’ before damage is done.”

He said ASIO had recommended visa cancellations when foreign agents had been identified trying to travel to Australia, and foreign agents had been intercepted at Australian airports.

He gave the example of a foreign “sleeper” who had quietly built community and business links while secretly maintaining contact with his offshore handlers.

“The agent started feeding his spymasters information about Australia-based expatriate dissidents, which directly led to harassment of the dissidents in Australia and their relatives overseas.

-with AAP