China will raise fuel surcharges for domestic flights by half from April 10, the country's top economic planner said on Thursday, moving to help struggling airlines after Beijing raised fuel prices this week.

The surcharge for each passenger flying less than 800 km (500 miles) will be raised to 30 yuan (USD$3.70) from 20 yuan, while those flying further need to pay a 60 yuan surcharge from 40 yuan, the National Development and Reform Commission said.

"The time for executing the new policy is temporarily set from April 10 to October 10," it said, leaving room for further changes.

China raised the ex-refinery price for aviation fuel by 300 yuan (USD$37.37) per tonne, or 6 percent, from last Sunday, as part of a package to help state refiners recover losses. It raised ex-refinery prices by 300 yuan per tonne and diesel by 200 yuan a tonne.

China has also revised its jet fuel pricing scheme to allow prices to float more freely from April 1, the first step toward a wider reform of the country's fuel price system.

The new system will allow domestic airlines and distributors to negotiate selling prices within an 8 percent band of an outright price that includes a set margin for distributors, said Chinese fuel importer, China Aviation (Singapore) Corp. (CAO).

Within two years, prices for domestic airlines flying on international routes should be fully liberalized, CAO said, removing a measure of price protection for airlines such as Air China. Foreign carriers already pay market prices.

The higher surcharge will provide much-needed relief for airlines, which are having to cope with high fuel prices, representatives said.

"The rise will increase company operating revenue and reduce pressure on our jet fuel expenses," said a spokesman at China Eastern Airlines, one of China's top three airlines.

"It's normal they should raise the surcharge -- everyone is worried about the high oil prices," said a spokesman from China Southern Airlines.