German antitrust authorities have fined 11 chocolate makers €60 million for colluding to rig the price of confectionary.

The Federal Cartel Office says the offences committed by companies including Kraft and Nestlé occurred between 2004 and 2008.

The offences include agreeing on how much to increase the price of chocolate bars when the cost of raw materials rose sharply in 2007.

The cartel office said in a statement that the companies "simply ceased competing with each other and piled the price rises on to consumers."

It said that Mars avoided a fine by alerting authorities to the illegal practices.