UPDATE 1-China's NDRC to propose to help power firms -report

(Adds share price action)

BEIJING, April 29 (Reuters) - Shares in Chinese power producers jumped on Tuesday after state media reported that China's top economic planner may submit a proposal to the cabinet within days, seeking assistance for power-generating firms squeezed by soaring coal costs and fixed power rates.

Officials from coal mines, power firms, the electricity regulator and some industry bodies were recently convened by the National Development and Reform Commission in a failed effort to forge a compromise solution, the China Business News said.

Still, "the commission would present its specific suggestions to the State Council as early as before the May Day holidays on how to ease tightness in coal supply", the newspaper reported, quoting an unnamed NDRC official.

The report did not detail the proposals, but said measures that were discussed included controlling coal prices, raising on-grid tariffs, providing subsidies or activating a pricing formula that would link coal and power prices.

Shares in top electricity producer Huaneng Power Internationah (0902.HK) jumped as much as 6 percent on Tuesday, while Datang Power (0991.HK) rose as much as 4.8 percent.

Smaller rival Huadian Power (1071.HK) soared 9 percent to HK$2.70 even as it posted a 92 percent fall in first-quarter earnings. [ID:nHKF079130]

China has kept power tariffs essentially unchanged since 2006 despite surges in the cost of coal, which fuels some 80 percent of the country's power generators, leaving power firms with declining profit margins and making them unwilling to stockpile much coal.

In addition, shipping bottlenecks and the shutdown of small coal mines had also reduced supplies, pushing up coal prices.

Coal stocks at major power plants had slipped to levels last week that cover 12 days of generation, down from 15 days in early March, and in some regions not enough for seven days of use.

China's five major power generating groups lost 2.7 billion yuan ($385.6 million) in the first quarter of this year, an executive with one of the firms was quoted as saying by the China Times on Monday.

Power prices will only be lifted after the summer Olympic Games and even then an expected hike of 0.04 yuan per kilowatt would likely be phased in, the newspaper added, quotingthe unnamed executive. ($1=7.002 Yuan) (Reporting by Jim Bai and Judy Hua in Hong Kong; Editing by Anne Marie Roantree)