Conservative Liberal backbencher Cory Bernardi may support a Labor bid to keep seized NBN documents under the lock and key of parliament.
Labor is confident it can prevent the Australian Federal Police from using thousands of seized documents as part of an investigation into leaked correspondence relating to the national broadband network.
Officers executed a search warrant at Parliament House in Canberra on Wednesday, but the material can't be accessed until the Senate determines whether they are covered by parliamentary privilege.
Senator Bernardi says he's seeking advice about the raids.
"I've always been of the view that parliamentary privilege is inviolable," he told Guardian Australia on Thursday.
"Depending on that advice, it may be appropriate for the privileges committee to consider the matter further."
Opposition Leader Bill Shorten was coy on whether he believed he had the numbers in the Senate, insisting he hadn't spoken to other parties about it.
"I'm always cautious about predicting numbers," he told reporters in Canberra.
"But what I do know is that we have got the right argument."
The government was desperate for bad news about the NBN not to get out, he said.
"Politicians need to be able to get information, there needs to be the institution of privilege.
"This is not a healthy sign for this government or indeed this country."
Shadow attorney-general Mark Dreyfus earlier said he was confident Labor would succeed in claiming parliamentary privilege over the documents.
Cabinet minister Simon Birmingham said claims of privilege were very serious matters.
"It should be used sparingly and cautiously," he said.
It was not there to cover up illegal activity, but an important principle to ensure people had confidence to go to parliamentarians with information.
Senator Birmingham refused to pre-judge the Senate's decision.
