Baker & McKenzie and Clifford Chance (CC) are understood to be advising on the IPO of Hong Kong airlines, estimated to worth approximately $500m.

The South China Morning Post (SCMP) last week reported that the airline was planning a dual-currency listing on the Hong Kong Stock Exchange (HKSE), denominated in both Chinese Yuan (CNY) and Hong Kong Dollars (HKD).

The carrier, which is owned by China's Hainan Airlines, has not yet publicly announced its plans or submitted its listing application to the HKSE, but is expected to launch the IPO in the fourth quarter of this year.

The deal would be significant for Hong Kong if successful, helping promote internationalisation of the renminbi.

Baker & McKenzie is understood to be advising the issuer on the deal, according to Legal Week sources familiar with the matter.

Advising the banks is thought to be magic circle firm Clifford Chance, with a team of partners in China and Hong Kong heading up. The SCMP reported that JP Morgan has been appointed as sole sponsor.

According to sources, Linklaters was originally mandated to represent the banks on the deal, but is no longer advising. CC was approached at a later stage.

Linklaters and CC declined to comment. Bakers did not respond to a Legal Week email.

Hong Kong's IPO sector has taken a hit in recent years following a downturn at the end of 2012 and Alibaba's decision to IPO in New York instead of the Asian financial hub.

A listing by Hong Kong Airlines would be a positive turn of events for the city's exchange, which is also soon expecting a revived listing by Chinese pork producer WH Group worthy approximately $3bn according to recent media reports.