WhatsApp has been fined over $3.3 million in Italy for 'forcing' users to share their personal data with its parent company Facebook.

The popular chat app has been asked by all of the 28 European Union data protection authorities to stop sharing users' data with Facebook as there were doubts over the validity of users' consent, Express.co.uk reported on Friday.

"We're reviewing the decision and we look forward to responding to officials," the report quoted a WhatsApp spokesman as saying.

Facebook took over WhatsApp in 2014 and in August 2016, it changed its privacy policy to allow the transfer of its users' personal information to the parent company for processing — a move that also created a furore in India. 

The Indian government told the Supreme Court in April that it was actively considering to put in place a law to protect data and curb sharing of individual data on social networking sites and online messaging services.

The petitioners challenged a September 23, 2016, Delhi High Court order which allowed WhatsApp to roll out its new privacy policy.

Although the high court did say that it could not share the data of its users collected up to September 25, 2016, with Facebook or any other related company.

During the acquisition, Facebook had claimed that respect for users' privacy was "coded into its DNA".

But Italy's antitrust regulator alleged that "the opportunity for WhatsApp users to refuse the handover of data to Facebook was available 'but it was inadequately flagged'."

The German authorities in April banned Facebook from collecting information on its WhatsApp users in the country, after it was found to have breached data protection laws. 

Since Facebook took over WhatsApp, it has been surrounded by controversies related to privacy. 

Earlier in 2017, The Guardian reported a security vulnerability that could be used to allow Facebook and others to intercept and read encrypted messages had been found within its WhatsApp messaging service.

WhatsApp denied the allegation saying it had a design decision relating to message delivery, with new keys being generated for offline users in order to ensure messages did not get lost in transit.