Analysys International, a research firm that tracks online car-booking market, said Didi Kuaidi took more than 80 percent of the market share while Uber, a remote No 2, controlled 16 percent at the end of the third quarter.

Didi Kuaidi's high market share was driven by its large taxi driver base, a segment that does not belong to chauffeur services.

Zhang Xu, a researcher from Analysys International, said the regulators' uncertain attitude toward car-hailing apps will remain the biggest hurdle for Uber, Didi Kuaidi and their challengers.

"The government needs to announce a clear policy as soon as possible to erase the uncertainty in the market," Zhang said.

Last month, the Ministry of Transport published a draft regulation that necessitated private cars to undergo a stringent registration process before being given access to car-hailing apps. The draft had evoked widespread criticism.

Liu from Uber said both app providers and the regulators will need a less strict "Plan B" to resolve the disagreement. But she admitted that it would be a time-consuming process.