Tony Abbott says he has no evidence Australia’s spy agencies have acted outside the law and argues current “stringent” safeguards work to prevent overreach by the intelligence services.

The prime minister on Monday batted away fresh calls for a thorough and far-reaching parliamentary inquiry into the activities of Australia’s intelligence agencies, telling reporters in Canberra he wanted the “long strong arms of Australia” to be zealous in protecting the country’s national security interests.

Abbott’s comments came in the wake of a new revelation by Guardian Australia that the Defence Signals Directorate offered to share a broad sweep of information collected about ordinary Australian citizens with its major foreign intelligence partners during a meeting in 2008.

The Greens, and the prominent human rights lawyer Geoffrey Robertson, are of the view that the conduct flagged by DSD with its “5-Eyes” intelligence partners in 2008, would, if carried out, see the Australian signals agency operating outside its legal mandate.

Labor’s Joel Fitzgibbon, who was the defence minister in 2008, gave a strong hint on Monday that he was completely unaware of the proposal being floated by the agency – now the Australian Signals Directorate – at the Cheltenham meeting.

Fitzgibbon told Sky News any surveillance activity involving Australian citizens would require ministerial signoff by both the defence minister and the attorney general. “This surprises me,” he said, declining to comment further.

The prime minister on Monday declined to confirm or deny whether the specific intelligence sharing flagged in the 2008 memo actually took place, saying he never commented on operational matters.

But he said he had no evidence that Australian intelligence had broken any law, or had been “over zealous”. Abbott said Australian agencies needed to be in a position to collect material to keep the public safe.

“Australia will act to protect our national interest and to protect our citizens,” he told parliament. “We always have under governments of both persuasions and, as far as I’m concerned, we always will – we will act to protect our national security.

“Our security agencies operate under very strict safeguards. They operate under the scrutiny and supervision of the joint parliamentary committee on intelligence, and under the scrutiny and supervision of the inspector general of security and intelligence.

“These are strong and effective safeguards.”

The Greens have called for a thorough parliamentary inquiry in the wake of Monday’s news report to establish whether intelligence agencies are acting in accordance with the law, and whether ordinary citizens need more privacy protections to ensure their normal online activities are not caught in any global dragnet.

The party is concerned that the material published by Guardian Australia indicates that Australian intelligence agents had a relatively casual attitude about privacy issues when compared with their counterparts, such as those in Canada.

The memo said the DSD indicated it could share bulk material without some of the privacy restraints imposed by other countries, such as Canada.

"DSD can share bulk, unselected, unminimised metadata as long as there is no intent to target an Australian national," notes from the 2008 intelligence conference say. "Unintentional collection is not viewed as a significant issue."

Scott Ludlam speaks to the media on Monday Guardian

The Greens communications spokesman Scott Ludlam said it was time for the major political parties in Australia to face up to the substantive questions posed by material leaked by the National Security Agency contractor and whistleblower Edward Snowden that suggested overreach by the intelligence services.

Monday’s revelation about possible data sharing among the 5-Eyes partners follows a revelation last month that Australia had tried in 2009 to listen in on the mobile telephones of the Indonesian president, his wife and their inner circle.

“It’s important to be clear about what’s at stake here,” Ludlam told reporters in Canberra. “Last week there were revelations about spying on heads of state. This week it’s about everybody else – the rest of us.”

Ludlam said the time had come for a thorough parliamentary inquiry “into surveillance overreach by these agencies”.

“It is essential now that these agencies be taken in hand, and things come out from behind closed doors,” he said.

Ludlam was backed by the South Australian independent senator Nick Xenophon, who described the revelations in the Guardian Australia report as “shocking”.

“These revelations from 2008 show that back then, the DSD was considering sharing information with the Australian federal police and National Security Agency,” he said. “You need to ask, five years on, how widespread this surveillance is.”

Xenophon also called on all Australian phone and internet companies to “come clean on any secret co-operation to facilitate the mass surveillance of Australians”.