HONG KONG, June 10 (Reuters) - Chinese copper smelters are considering an anti-dumping filing against sulphuric acid imports from Japan and South Korea, smelter sources said on Wednesday.

Chinese prices of sulphuric acid have fallen to about 6 percent of the price a year ago, causing losses for Chinese smelters, which produce it as a by-product of copper and zinc smelting.

'Smelters had a meeting to discuss that move and now they are discussing the matter internally,' said a source at Tongling Nonferrous Metal, the country's second-largest copper producer, which produces nearly 2 million tonnes of sulphuric acid a year.

He said a formal anti-dumping filing was likely to depend on the response of the Ministry of Commerce, which is in charge of accepting and investigation of anti-dumping cases in China, the world's top consumer and producer of many base metals.

Chinese copper smelters may be forced to cut production if they can not sell their sulphuric acid production and have insufficient storage space, the Tongling source said.

'Japan and South Korea are dumping (sulphuric acid),' said Pan Qifang, spokesman for Jiangxi Copper, the country's top copper producer.

'If there is an anti-dumping filing, we will join,' Pan told Reuters.

Jiangxi Copper, capable of producing more than 2 million tonnes of sulphuric acid a year, was forced to cut copper production in early 2008 because of a lack of storage space for sulphuric acid after China's snowstorms damaged roads in many provinces and slowed the firm's shipments.

Sulphuric acid was trading at around 90 yuan per tonne, a big fall from 1,550 yuan a tonne a year earlier because of increased imports from Japan and South Korea and reduced demand, Pan said.

The Tongling source said the production cost of the acid to smelters was around 150-180 yuan per tonne on average.

Prices for imported sulphuric acid had stood at $3-$10 per tonne at Chinese ports, equivalent to 21-68 yuan, according to Chinese media.

A source at one copper smelter in Japan said exports of sulphuric acid to China remained regular, without providing export prices.

China imported 1.14 million tonnes of sulphuric acid in the first four months of this year, up 68 percent on the year, with the bulk coming from Japan and South Korea, Chinese media has reported.

(Additional reporting by Miho Yoshikawa in TOKYO)