Google publicised its new privacy rules which regulate how the Web giant uses the enormous amounts of personal data its collects through its search engine, email and other services with much fanfare last week.

Since then, it has launched a huge publicity campaign informing its users around the globe of the new policy, which is set to come into force on March 1.

But that launch date may now be under threat.

In a letter to Google Chief Executive Larry Page, Jacob Kohnstamm, the chairman of the group of 27 national privacy regulators in the EU, said the French data protection agency has started a probe of the new rules and how they will affect Google users in the EU.

"We call for a pause (in the rollout of the new rules) in the interests of ensuring that there can be no misunderstanding about Google's commitments to information rights of their users and EU citizens, until we have completed our analysis," Kohnstamm wrote in the letter, which was sent yesterday and published today.

Google's search engine has a market share of more than 90 per cent in the EU, with rival services like Microsoft's Bing gaining little traction.

The EU's competition authorities are already examining whether Google uses this dominance to stop other search engines from entering the market.

The new policy makes it easier for Google to combine the data of one person using different services such as the search engine, YouTube or Gmail if he is logged into his Google account.

That allows Google to create a broader profile of that user and thus target advertising based on that person's interests and search history more accurately. Advertising is the main way Google makes its money.

But the company argues that combining the data into one profile also makes search results more relevant and allows a user to cross-navigate between different services more easily.

Google said in a statement on Friday that it had briefed data protection agencies before making its new policy announcement and that none of them had had substantial concerns at the time.