China's state-owned Beijing Enterprises Group Co Ltd (BJEG) has again raised its stake in bid target China Gas Holdings Ltd, taking its holding to 20.3 percent, a filing with the Hong Kong securities regulator showed on Thursday.

BJEG, parent of utility Beijing Enterprises Holdings Ltd , has been consistently building its stake in China Gas, which has rebuffed a $2.2 billion joint takeover offer from ENN Energy Holdings Ltd and China Petroleum & Chemical Corp (Sinopec) .

Last week, ENN and Sinopec extended their offer for China Gas by a month to Aug. 6 as they wait for regulatory approvals for the deal.