AFP raids Labor offices over NBN leaks

The Australian Federal Police has raided Labor Party offices in Melbourne as part of an investigation into leaked documents concerning the national broadband network.

On Thursday night members of the AFP raided the office of Labor senator and former Communications Minister Stephen Conroy, as well as the homes of two staffers for Shadow Communications Minister Jason Clare, Shadow Attorney-General Mark Dreyfus confirmed. Clare's office has been contacted for comment.

"Tonight's events are unprecedented - we have never witnessed such an extraordinary action during a federal election campaign," Dreyfus said in a statement.

Opposition Minister Bill Shorten labelled the raids "an extraordinary development".

Labor frontbencher Tony Burke suggested to ABC's 730 that the government had improperly influenced the AFP to raid the Labor office.

"There's no doubt that the documents that came from the NBN caused immense damage to Malcolm Turnbull when they showed the cost blowout of the NBN, the fact that it was slower, the fact that it was going to be delayed," Burke said.

"I make no criticism of the AFP at all. I simply know that when there have been leaks, even from the national security committee of this government, when there have been government staffers walknig around [this] building handing out cabinet-in-confidence documents, the government hasn't previously acted on referrals to the AFP," Burke said.

Finance Minister Matthias Cormann denied the raid was politically motivated.

'The AFP is an entirely independent organisation and makes their own judgement on those things,' he told 730.

Fairfax Media reported as many as 20 NBN staff had been interviewed by the AFP as part of the investigation into the leaks.

NBN spokesperson Karina Keisler confirmed the NBN referred the staff members to the AFP.

Four separate documents have leaked out of NBN since November last year, two of them in the same week.

A February leak of an internal progress report revealed the NBN was running behind on its fibre-to-the-node rollout and that costs per connection were rising.

Two previous damaging leaks in November and December last year revealed separately that NBN was considering overbuilding the degraded Optus HFC network, and that it is facing a remediation bill for Telstra's copper of ten times more than it expected.

Further leaked documents in March detailed NBN's plans to deploy skinnier fibre to address expensive duct blockage problems with existing cables.

Update: The AFP today said the investigation had been underway since December 9 when it received a referral from NBN.

"This investigation has been undertaken independent of government, and decisions regarding yesterday’s activity were made by the AFP alone," the force said in a statement.

It said its next step would be to examine and analyse the material collected from the Labor offices and homes during the raids.

The AFP confirmed it interviewed "a number" of NBN staff yesterday. 

"This investigation remains ongoing, and the AFP will provide further detail when it is appropriate to do."