Chinese companies Sinopec and ENN Energy have set a deadline for their joint hostile acquisition bid for gas distributor China Gas Holdings, signaling the end of a process stretching back to an initial offer last December is nearing.

In a filing to the Hong Kong stock exchange on Wednesday night, the duo said they have extended their offer to within seven days of October 15, which would put the latest date at October 22.

This was following notification by the Securities & Futures Commission that their offer should not extend indefinitely and were requested to set a definitive date, they said in the filing.

The duo mounted an all-cash HK$3.50/share offer for China Gas in December in a deal valued at HK$16.7 billion ($2.2 billion). ENN has a 55% stake in the bidding joint venture while state-owned Sinopec has 45%.

On August 6 they extended the long-stop date -- the deadline for pre-conditions set out in the indicative offer to be met, including government approval -- to September 6. This was the fourth extension since March.

The companies are still waiting on approvals from various Chinese regulatory bodies and ministries for the deal, including applications to the National Development and Reform Commission, the Ministry of Commerce and the State-owned Assets Supervision and Administration Commission.

China Gas has rejected the offer as too low and said its shareholders are against the acquisition as its shares have consistently traded higher than HK$3.50 for much of this year.

On Thursday, its Vice President and Executive Director Kevin Zhu said in an emailed statement that the company welcomed the news that the SFC has requested a deadline for the offer.

"Almost nine months have elapsed since the possible offer was announced and it remains pre-conditional. This is extremely frustrating to the management, employees and key shareholders of China Gas, all of whom have made it patently clear that they are unwilling to consider the consortium's offer, which significantly undervalues the business and is 16% below yesterday's closing price of $4.16," he said.

"We cannot understand why the consortium has made the decision to press ahead with an offer which has almost no chance of success, prolonging the uncertainty for all stakeholders, including its own," he added.