Brussels has launched surprise raids at Europe's largest container lines today as it kicked off a huge price fixing investigation.

European Commission investigators have begun riffling through documents at AP Moller-Maersk, CMA CGM, Hapag-Lloyd, Hamburg Sud and Neptune Orient Lines after marching in to their offices this morning.

It is not immediately clear what sparked the dramatic action, which is capturing headlines around Europe today.

Early reports in Denmark suggest Maersk Line could face a $1bn fine, but the company and the Commission have both pointed out there is no evidence to suggest wrongdoing at this time.

In a statement the Commission says it has “reason to believe that the companies concerned may have violated the antitrust rules that prohibit cartels and restrictive business practices and/or abuse of a dominant market position".

It is not immediately known whether any documents have been taken away from the liner giants today but sources say it would be standard practice to do so.

Maersk says it is cooperating with the investigation and had stressed its innocence.

Its legal chief Christian Kledal said in a statement: “Unannounced inspections are a preliminary step in European Commission investigations into suspected infringements of competition rules. However, the fact that the Commission carries out such inspections does not mean that the company has engaged in anti-competitive behaviour nor does it prejudge the outcome of the investigation itself.

He added: “It is our clear opinion that our practices are in compliance with EU competition legislation, and we fully cooperate with the Commission’s employees to investigate the matter thoroughly.

“For several years we have implemented our compliance programme which includes guidelines and training of employees etc. in order to ensure, to the widest extent possible, that our employees are aware of legislation and how to adhere to it.”

CMA CGM, Hapag-Lloyd Hamburg Sud and Neptune Orient Lines also confirmed the Commission has entered its offices.

Hapag-Lloyd said the EU was investigating possible breaches of the law since the abolition of the liner shipping conferences block exemption in October 2008.

MSC refused to answer questions on today’s events when contacted by TradeWinds this afternoon.

Shipping is no stranger to brushes with the European Commission.

Class societies including DNV and Lloyd’s Register were raided in early 2008 amid claims of collusion.

Last year the spotlight fell on members of the International Group of P&I clubs.