China moved on Tuesday to tighten control of its technology sector, publishing detailed rules aimed at tackling unfair competition and companies’ handling of critical data.

Beijing has been firming its grip on Internet platforms in recent months, citing the risk of abusing market power to stifle competition, misuse of consumers’ information and violation of consumer rights, in a reversal after years of a more laissez-faire approach.

The country issued hefty fines to companies including e-commerce giant Alibaba Group and social media company Tencent Holdings as part of a widening crackdown and has vowed to draft new laws around technology innovation and monopolies.

On Tuesday, the State Administration for Market Regulation issued a set of draft regulations banning unfair competition and restricting the use of user data. New York-listed shares of Alibaba, JD.com Inc and Baidu Inc fell between 2.9 per cent and 3.5 per cent in premarket trading.