Attorney-General George Brandis is facing pressure to give a further statement on why a Canberra lawyer's office was raided by ASIO, as Prime Minister Tony Abbott says the government is committed to protecting national security.
Labor and the Greens are calling on Attorney-General George Brandis to give a more detailed statement on an alleged spying operation in East Timor.
East Timor is launching arbitration in The Hague on Thursday to tear up a multi-billion-dollar oil and gas revenue-sharing treaty with Australia.
Asked about the raid, Prime Minister Tony Abbott said the government was committed to protecting national security.
"We don't interfere in (court) cases, but we always act to ensure that our national security is being properly upheld - that's what we're doing," he told reporters.
"One of the important things that government does is protect national security."
Lawyers for the tiny nation argue the Howard government used the Australian Secret Intelligence Service (ASIS) to spy on the East Timorese government to give Australia an unfair advantage in talks over the resources deal and a benefit to Woodside.
On Wednesday, officers from Australia's domestic intelligence agency, ASIO - on the orders of Senator Brandis - raided the Canberra office of lawyer Bernard Collaery, who is in the Netherlands preparing for the case.
ASIO officers also reportedly interviewed a former senior ASIS agent who was expected to give evidence at The Hague, and cancelled his passport.
Mr Collaery says the ASIS agent had decided to blow the whistle on the 2004 operation because former foreign minister Alexander Downer had, after leaving politics, become a lobbyist for Woodside.
Senator Brandis released a brief statement on Tuesday night saying he had approved warrants to carry out the Canberra office raid, but denied it was aimed at impeding the court case.
He said he had instructed ASIO that any material taken from the lawyer's office was not to be communicated with those conducting the court case.
Opposition Leader Bill Shorten has sought a government briefing on what he described as a "serious matter", but he declined to comment further.
The Greens on Wednesday failed to secure Labor's support to force Senator Brandis to give a full explanation to parliament.
But opposition leader in the Senate Penny Wong said Senator Brandis should be "encouraged" to make a further statement.
"These are important matters and they do go to the integrity of the rule of law," she said.
"And for that reason the Senate ... would benefit from a statement from the attorney-general on this matter."
Greens spokesman Senator Scott Ludlam said the motion to force the attorney-general to make a statement would not be necessary if it was a case of ASIS bugging al-Qaeda or an international criminal syndicate.
"But what is at stake is an apparently well-founded accusation ... that ASIS bugged the cabinet rooms of the government of Timor-Leste during sensitive commercial negotiations that have consequences in the billions of dollars for commercial players like Woodside," he said.
"That has nothing whatsoever to do with national security."
Liberal frontbencher Mitch Fifield said the Senate needed to remember there were long-standing and bipartisan conventions in relation to commenting on national security matters.
But he hinted at a further statement being made, saying Senator Brandis "does pay close attention to contributions of colleagues in this place".