UPDATE 1-Vietnam eyes steep tax increases on mining, gas, coal

(Adds foreign investment, tax revenues)

HANOI, Aug 20 (Reuters) - Vietnam's Finance Ministry has proposed steep tax hikes on domestic production of minerals, metals, natural gas, coal and gemstones to help protect the environment and prevent unauthorised mining.

Foreign firms operating, or planning to invest in Vietnam's energy and steel sectors that could be exposed to the tax include BP Plc (BP.L: Quote, Profile, Research), Gazprom (GAZP.MM: Quote, Profile, Research) and Tata Steel (TISC.BO: Quote, Profile, Research).

Vietnam vies with the United States as the world's seventh biggest exporter of thermal coal and is Southeast Asia's third-largest producer of crude oil.

For a factbox on foreign investment in Vietnam, click on [nHAN192885].

"Raising the natural resource tax on minerals will contribute to limiting the widespread exploitation and raising revenues for provincial budget to help improve the environment," the ministry said in a statement seen on Wednesday.

Taxes on mining manganese, steel, lead, zinc, copper and tin would be raised to between 10 and 30 percent, from 1-5 percent now, the ministry said in its draft proposal obtained by Reuters.

Natural gas production would be taxed at 6-25 percent, on par with the current tax on crude oil and up from zero to 10 percent now, while coal mining would be taxed at between 5-20 percent, from 1-3 percent at present.

Taxes on mining of stone construction material, soil and sand would be raised to 5-10 percent from 1-5 percent, it said.