Web giant Google failed to make any of the changes to its privacy policies that were requested by a consortium of EU data protection regulators last year.
The investigation found that Google had not given customers enough information about the change, and in October it asked Google to limit the amount of data it collects from users.
It is now up to the national regulators of each of the six countries – the UK, Italy, German, Spain, the Netherlands and France – to investigate whether Google broke their local data protection laws.
"The action follows an initial investigation by the French data protection authority CNIL, on behalf of the Article 29 group of which the ICO is a member," the statement read. "Several data protection authorities across Europe are now considering whether the policy is compliant with their own national legislation.
“As this is an ongoing investigation it would not be appropriate to comment further.”
The European Commission has proposed reforms to the EU's data protection regime that would harmonise national laws. This is being opposed by the UK's Ministry of Justice, however, on the grounds that it might limit the UK's digital economy.
Google was recently fined $7 million for allowing its Street View cars to download information on people's browsing habits and other personal data from unsecured wifi hotspots when taking photographs of neighbourhoods in 2010.
Earlier this week, Google's privacy director Alma Whitten announced she was stop step down from the company after three years in the role. “The privacy and security teams, and everyone else at Google, will continue [our] hard work to ensure that our users’ data is kept safe and secure," Google said in a statement supplied to media outlets.