Google's practice of pre-installing its Chrome browser and search tool on Android devices is a breach of EU antitrust rules, the European Commission has said. 

The Commission has filed formal proceedings against the search giant, based on the belief that it is closing off ways for rival search engines to access the market. 

"We believe that Google's behaviour denies consumers a wider choice of mobile apps and services and stands in the way of innovation by other players," Competition Policy Commissioner Margrethe Vestager said. 

Google has 12 weeks to respond. In a blog post addressing the charges, the company said that it looked forward "to working with the European Commission to demonstrate that Android is good for competition and good for consumers."

The Commission found three objections to Google's business practices: that it requires manufacturers to pre-install Google Search and Chrome and set them as default apps on devices; that it prevents manufacturers from selling smartphones with other operating systems based on Android's open source code; and that it used financial incentives to ensure manufacturers exclusively pre-installed Google products on their devices.  

About four out of every five smartphones in the world run on Google's Android operating system. Google also holds more than 90 per cent market share in the internet search and app store sectors across the European Economic Area. 

The Commission first opened these antitrust proceedings against the company in April 2015. They are distinct to other proceedings against the company, with the European Commission and the search giant having clashed heads on other issues related to search, scraping, advertising exclusivity and undue restrictions on advertisers.