NBN claims top-secret classification on leaked docs: Conroy

The documents behind a series of damaging leaks on the state of the National Broadband Network (NBN) rollout have been claimed as having top-secret classification by NBN, Senator Stephen Conroy has said.

Speaking to The Guardian while the Australian Federal Police (AFP) continued its raid on Parliament House last night, the senator said his office was told that national security matters were involved.

"NBN Co has claimed the documents are top secret ... as the former minister for communications and the minister who established the NBN Co, there are no documents produced inside NBN Co that would come within a bull's roar of being top secret," Conroy said.

"We sought to record today's events, and my staff were informed they were not allowed to record the events because there were national security matters at stake."

Conroy said his office had filmed the raid conducted during the election campaign, and that the footage was used to reveal the AFP had allowed an NBN employee to attend the raid.

NBN chairman Ziggy Switkowski previously claimed that the documents were stolen, in a column that Secretary of the Department of the Prime Minister and Cabinet Martin Parkinson found breached the caretaker conventions that dictate how government departments and businesses are to behave during an election.

On that charge, Conroy said theft is usually a state matter, so it is a mystery why the Australian Federal Police continue to be involved.

Despite NBN having used the well-worn commercial-in-confidence excuse to avoid scrutiny during his time as communications minister, Conroy said NBN could not use that reasoning as justification for calling in the AFP.

"There is no commercial-in-confidence when you are established as a public-sector monopoly, there's no commercial-in-confidence issues at all," he said.

For its part, NBN said it operates critical national infrastructure and was well within its rights to refer theft or other criminal matters to police.

"It is a matter for the AFP as to whether they accept the referral and pursue any matter, based on their own independent advice and judgment," an NBN spokesperson said.

The documents seized by the AFP during its pair of raids have had parliamentary privilege claimed on them by Conroy, meaning they are now sealed and sit with the Clerk of the Senate pending a determination on whether parliamentary privilege applies to them.

"It's of vital importance that parliamentary privilege is honoured," Shadow Attorney-General Mark Dreyfus said on Wednesday. "It is vital to the way in which parliamentarians go about doing their work.

"It protects documents that they obtain or documents that they create as part of doing their work, which, in the present situation, is work that concerns the accountability of a government-owned corporation which is spending billions and billions of dollars of public money."

Opposition Leader Bill Shorten said the government is overreaching on the issue.

"I cannot believe the extent to which this government will go to cover up its NBN stuff-up," Shorten said on Wednesday.

"At the end of the day, the public have a right to know if billions of dollars are being wasted."

Prime Minister Malcolm Turnbull has accused Senator Conroy of meddling in the course of justice and bullying the AFP.

"As for him trying to use political influence to stop an investigation ... he should know better," Turnbull said.

NBN is scheduled to release an updated Corporate Plan on Friday.

Updated 8.23 am AEST 26 August 2016: Additional NBN comment