The Transport and Logistics Bureau has assured lawmakers that fares won't be affected by the coming merger of Citybus and New World First Bus, and any reductions in routes will be done gradually.

At a Legco panel meeting on Friday, the bureau's permanent secretary, Mable Chan, was asked whether passengers will be negatively affected by the merger, since some routes of the two bus operators are similar but have different prices.

Chan said fares will not be affected by the merger.

"When we consider routes restructuring and integration, whether the fares will be accepted by the people and can enable sustainable operation... all these factors will be taken into account," she said.

"We totally agree such integration needs to be done gradually."

She also said that fares could be reviewed more frequently to avoid sudden, sharp increases, though she rejected the idea of tying fares to inflation, saying doing so would be inflexible.

The official said the merger will hopefully allow the bus operators to save costs by deploying resources more efficiently, noting that both Citybus and New World First Bus have been making a loss since 2017.

She said the operators have also pledged to improve bus stop facilities and services after the merger.