The European Commission has said that Google's Buzz is in line with the bloc's data protection guidelines, while 10 national regulators from Canada to the UK are demanding that Google must change the privacy controls of the social networking site.
The UK is the latest country to join Canada, France, Germany, Spain and five others to complain about a lack of fundamental privacy controls on the site, while the EU is satisfied that Google's Buzz is in step with EU data protection principles.
As far as the EU is concerned, as long as users' data is not used without their prior and tacit consent, then Buzz has not broken any laws.
Gmail users are automatically signed up to the Buzz site unless they intentionally opt-out.
However, the national privacy regulators' complaint stems from growing concerns over how Google uses the private information of Gmail account holders. They insist that users should have "complete control" over the use of their personal details.
In a letter sent on Monday (19 April) to Google Chief Executive Eric Schmidt, the regulators said Buzz had shown a "disappointing disregard for fundamental privacy norms and laws".
The letter not only referred to the social networking site but also to the company's StreetView mapping service.
In a statement, Google said it had addressed the regulators' concerns earlier in the year and did not wish to return to the issue again. But the company did admit that it did not get everything right all the time.
"Of course we do not get everything 100% right. We try very hard to be upfront about the data we collect and how we use it, as well as to build meaningful controls into our products."
A spokesperson for the European Commission said that while the EU executive cannot pursue individual companies, it will cooperate with national data protection authorities to ensure that EU rules on data protection are respected.
"It is up to the member states to verify whether the amended privacy settings by Google (following data protection concerns from several sides) regarding their Buzz service comply to this prior informed consent principle," the spokesperson added.