Mike Burgess, the head of the Australian Security Intelligence Organisation, said the group was disrupted last year, but not before recruiting an Australian official with "access to sensitive details of defence technology".

"The spies developed targeted relationships with current and former politicians, a foreign embassy and a state police service," Burgess said in a speech late Wednesday.

He declined to name the foreign agency involved but said it "was not from a country in our region".

"They tried to obtain classified information about Australia's trade relationships," he said.

"They asked a public servant to provide information on security protocols at a major airport."

The foreign intelligence officers have since been removed from Australia, Burgess said.

Australia's usually hyper-secretive spy agency ASIO has come out of the shadows in recent years, as it tries to deter adversaries, boost recruitment and be seen as more transparent.

Burgess has become more outspoken in particular about the threat from intelligence agencies operating in Australia, as concerns have grown about the Chinese government's more aggressive efforts to build influence in the region.