UPDATE 1-China fuel wholesalers to keep over 15 days' stocks

BEIJING, April 21 (Reuters) - China will from May 1 require wholesalers of refined oil products to maintain stocks equivalent to at least 15 days of sales, in an effort to reduce recurrent shortages and rationing that have plagued the country for months.

China's oil majors Sinopec (0386.HK: Quote, Profile, Research, Stock Buzz)(SNP.N: Quote, Profile, Research, Stock Buzz) and PetroChina (0857.HK: Quote, Profile, Research, Stock Buzz)(PTR.N: Quote, Profile, Research, Stock Buzz), had already boosted their gasoline and diesel imports in April and May, from already-high March levels, as they seek to bolster stocks ahead of the Beijing Olympics.

The shortages have been caused largely by state-set pump prices, which are so low that refiners lose money on processing so cut back on their output.

Beijing is reluctant to raise fuel prices because it is battling inflation, which is at its highest level for more than a decade, and instead has brought in a range of tax cuts aimed at slowing refiners' slide into the red.

Earlier this month, it extended a value-added tax rebate covering fuel imports into the second quarter, and is expected to bring in a similar discount to the cost of crude imports.

China is still setting up the first phase of its national strategic crude reserves, but it has learnt from abroad that refined oil products' traders should have a commercial reserve to minimise variations in price and supply.

The new requirements will strengthen China's ability to manage the market and prevent market fluctuations, the Ministry of Commerce said in statements posted on its website (www.mofcom.gov.cn).

Fuel wholesalers also will be required to have an annual turnover of at least 100,000 tonnes, while storage firms should reserve at least 60 percent of their capacity for customers rather than for their own use, according to the ministry.

The rules are a more detailed update to regulations governing the refined oil products market, which were published in 2006.

(Reporting by Jim Bai; Editing by Emma Graham-Harrison)