Calls are growing to out a former politician who was revealed to have helped a foreign spy ring.

ASIO Director-General Mike Burgess used his annual threat assessment address on Wednesday night to reveal a unit within a foreign spy service is targeting Australia.

The “A-team”, or Australia team, managed to recruit a politician who “sold out their country, party and former colleagues to advance the interests of the foreign regime”.

The former politician also attempted to introduce a prime minister’s family member to the spies, but the plot did not go ahead.

The opposition and former Liberal treasurer Joe Hockey have called for the person to be publicly outed, arguing keeping their identity hidden smeared all politicians and created distrust among Australia’s allies.

“You can’t make an allegation about someone being a traitor and then expect that no one will ask questions,” Hockey told Sydney radio 2GB on Thursday.

Opposition Leader Peter Dutton said: “If he doesn’t indicate the name, then there’s a cloud hanging over everybody else.”

He said he would “put my money” on a former NSW Labor politician and the country being China, but didn’t offer any evidence or further details.

Opposition foreign affairs spokesman Simon Birmingham also called for clarity on who the person is but his Liberal colleague was more wary about revealing the identity with foreign interference laws not applying retrospectively.

Opposition home affairs spokesman James Paterson said: “Given that, ... it would be unfair to name someone publicly and you would obviously be running a very serious defamation risk if you do so.”

The coalition would work with the government to amend the necessary legislation to make foreign interference laws retrospective, Dutton said.

“I wouldn’t have any hesitation supporting a discussion around that being made retrospective,” he said.

“The most egregious act is from somebody in public office who betrays their country, and I wouldn’t have any tolerance for it whatsoever.”

Defence Minister Richard Marles says he supports ASIO's decision. Photo / Getty Images

Speculation about the former politician wasn’t helpful, Defence Minister Richard Marles said as he backed the decision made by ASIO.

“I am not aware of the specific facts which underpin the scenario that Mike Burgess has outlined and I respect the reasons why that is important to be kept confidential,” he said.

“The other point here is the circumstances of the evidentiary base behind them.”

Asked why he didn’t out the former politician, Burgess said Australia was a “rule of law” country and the person wasn’t active anymore.

“They’re not doing it now, they’re not breaking the law,” the director-general said.

But they would be caught if they started doing it again, he said.

“Several individuals should be grateful the espionage and foreign interference laws are not retrospective,” Burgess said.

Foreign spies posed as consultants, head-hunters, local government officials, academics and researchers and targeted students, academics, politicians, businesspeople, law enforcement officials and public servants, he said.

They offered cash for information, with premiums for insider details.

Environment Minister Tanya Plibersek revealed she had previously reported to ASIO approaches that had been made towards her.

The ring also flew academics and political figures to another country for an all-expenses-paid trip where they ended up meeting spies disguised as bureaucrats.

Weeks later, the “A-team” then managed to pry information about Australia’s national security and defence from an academic.

Blowing their cover had put the entire operation on notice, Burgess said.

He also expressed frustration at suggestions “convictions are the only weapon in our collective arsenal or the only measure of our success”.

Other actions included working with partners to cancel visas, directly confronting spies or their organisations and issuing public rebukes.

Burgess said he had spoken with his counterparts from other nations and told them to stop their actions or face reprisals, “and they usually do”.

His remarks came just before former Liberal Party candidate Di Sanh Duong, 68, on Thursday became the first man found guilty under Australian foreign interference laws.

He will spend at least 12 months behind bars.