China's gas shortage to give a small boost to gasoline

* Taxis to shift to gasoline from CNG

* Industries hit, no immediate signs of fuel shift

* Oil firms pumping gas at top capacities

BEIJING, Nov 19 (Reuters) - A gas shortage that has hit central and eastern Chinese provinces will give a small boost to gasoline sales by China's oil duopoly, as slower gas supplies force taxis to gas stations, industry officials said on Thursday.

But as taxis burning the clean fuel are heavily concentrated in one region -- the southwestern province of Sichuan and Chongqing municipality -- the impact on China's gasoline balance will be marginal. China is Asia's leading gasoline seller.

In central city of Wuhan, capital of Hubei province, thousands of cabs turned to petrol kiosks after stations that pump compressed natural gas (CNG) suspended sales from Monday.

"The taxis have no choice but to shift to gasoline. Both PetroChina and Sinopec have lowered petrol prices for them," said a marketing official with top refiner Sinopec Corp (0386.HK) based in Wuhan.

Unseasonally early and heavy snow in northern China this winter caused a spike in gas use for heating, diverting supplies and hitting public transport and industries.

In Chongqing, locals reported long queues of taxis lining up for CNG, which goes into a tank installed in cabs' back trunks. Many were reluctant to shift to gasoline which is triple the cost of CNG.