The Australian Federal Police (AFP) are searching Parliament as they investigate documents leaked from the National Broadband Network (NBN) company.

Australian Federal Police (AFP) Commissioner Andrew Colvin said the matter was referred to his agency in December 2015 by NBN Co, not the Federal Government.

The ABC has seen a warrant relating to the raids carried out in May which suggests police are casting a wide net in their investigation.

It names Labor Senator Stephen Conroy, staffers, technology bloggers, and four major media organisations including the ABC.

It required the people subject to the warrant to hand over all documents relating to those people and organisations.

How are the searches at Parliament House different?

Police officers need to give prior notice of and seek permission to enter Parliament House and the areas immediately surrounding the building on Capital Hill.

In 2005 a Memorandum of Understanding between the Presiding Officers (the Speaker of the House of Representatives and the President of the Senate), the Attorney-General and the Minister for Justice set out guidelines to be followed in the execution of search warrants in relation to premises used or occupied by Members and Senators, including their offices in Parliament House.

It stated the politicians, or a senior staff member, should be present at the time of the search and should also be given "reasonable time" to consult the relevant presiding officer — the Speaker or the President of the Senate — as well as lawyers.

It further stated that search warrants may not be executed on sitting days.

This has happened previously: in 1998, police issued a search warrant for the parliamentary and electorate offices of Senator Arthur Crane.

What's the link between NBN co and the Government?

NBN Co is a Government-owned corporation, charged with constructing the National Broadband Network.

The company's constitution states "the company's objects are to roll-out, operate and maintain a national wholesale broadband network while working closely with the Commonwealth during the implementation study in order to facilitate the implementation of Australian Government broadband policy and regulation."

What does it mean that Labor has claimed parliamentary privilege on the seized documents?

Labor has claimed the documents seized by AFP during the raids are subject to parliamentary privilege.

The AFP has guidelines about how to deal with carrying out search warrants where parliamentary privilege may be involved.

It says "parliamentary privilege applies to any document or other thing which falls within the concept of 'proceedings of parliament'".

That includes "documents sent to a senator, which the senator then determined to use".

The documents are sealed in a bag to be considered by the Senate as to whether privilege does indeed apply.

However, the Senate is not sitting at the moment — so the matter won't be investigated until Parliament returns next week.

The 2005 Memorandum of Understanding between the presiding officers, the Attorney-General and Minister for Justice also noted that the member of Parliament involved may be given an opportunity to make copies of the documents.

Why are people talking about whistleblowers?

Labor Senator Stephen Conroy has voiced concerns about the protection of whistleblowers in relation to the searches, something dismissed by Communications Minister Mitch Fifield.

According to a Senate Committee report issued in April, a whistleblower "is commonly understood to be a person with insider information of misconduct who makes a decision to report or disclose that information".

"They are different to a customer, members of the public, or others who have evidence of and report organisational misconduct," it states.

However, the legal definition remains vague and — as the Senate Committee noted — "fundamental questions remain as to who can receive legal recognition as a whistleblower and the circumstances in which they can access whistleblower protections".

Labor claims that as NBN Co is not a public authority or Commonwealth entity, it is not entitled to special protections from disclosure of information.