China Petrochemical Corp (Sinopec Group), the country's top oil refiner and producer, is planning to launch an IPO of its gas station and convenience store unit in Hong Kong, a report said Monday.

The State-owned oil major aims to raise more than $5 billion by carving out its 30,000 gas stations and 23,000 convenience stores spread across China in an Hong Kong IPO, the Wall Street Journal reported Monday, quoting an unidentified source.

The company will pick banks for the IPO after the Chinese Lunar New Year holidays, which are from February 19 to February 21, said the report.

Sinopec did not respond to the Global Times' request for comment by press time.

Sales business is one of the most profitable segments of Sinopec, as its subsidiary Sinopec Sales Co can buy oil below-market price from Sinopec's other subsidiaries which are  in charge of petroleum processing, Liang Jun, a research fellow with the Guangdong Academy of Social Sciences, told the Global Times on Monday.

As of the end of 2013, Sinopec Sales Co operated 30,338 gas stations and sold 165 million tons of gasoline in the domestic market, accounting for 60 percent of the overall market, Sinopec said in a statement on its website in June 2014.

The Sinopec Sales Co achieved 476.4 billion yuan ($76.79 billion) in revenue in the first four months of 2014, the statement said.

The Hong Kong IPO, if launched, will be a big step in the company's mixed-ownership reform encouraged by the central government to reinvigorate the State-owned sector, Liang said.

Its rival PetroChina Co reportedly has launched a pilot program in Northwest China's Xinjiang Uyghur Autonomous Region for such reforms as well.

Sinopec announced on September 14 that it will sell a 29.99 percent stake in its wholly owned subsidiary Sinopec Sales Co to 25 companies in China and abroad for 107.1 billion yuan.

The move had got approval from the National Development and Reform Commission and the Ministry of Commerce by December 31, 2014, Sinopec said in a statement on its website on January 5.

These 25 domestic and foreign companies can benefit from the IPO, said Liang.