Facebook subsidiary WhatsApp faced a barrage of complaints by the European Consumer Organisation (BEUC) and others on Monday.
It said the changes will permit users to message businesses and would not affect personal conversations.
BEUC and eight of its members criticised the changes saying WhatsApp was unfairly pressuring users to accept its new policies.
"The content of these notifications, their nature, timing and recurrence put an undue pressure on users and impair their freedom of choice. As such, they are a breach of the EU Directive on Unfair Commercial Practices," the groups said in a joint statement.
"WhatsApp has failed to explain in plain and intelligible language the nature of the changes... This ambiguity amounts to a breach of EU consumer law which obliges companies to use clear and transparent contract terms and commercial communications," they said.
'No change to your personal chats'
The groups urged the European network of consumer authorities and EU data protection authorities to work together to address these privacy and consumer rights concerns.
In a statement to Euronews Next, WhatsApp responded by saying the privacy and security of personal chats on the app would not change.
"BEUC’s action is based on a misunderstanding of the purpose and effect of the update to our terms of service. Our recent update explains the options people have to message a business on WhatsApp and provides further transparency about how we collect and use data.
"The update does not expand our ability to share data with Facebook, and does not impact the privacy of your messages with friends or family, wherever they are in the world," a company spokesperson said.