Power usage curbs in China have cut demand for refined tin, as solder companies and tin chemical producers in parts of the country are operating at reduced capacity, the International Tin Association's (ITA) Beijing branch said on Monday. 

London tin fell as much as 4.8% to $34,800 a tonne on Monday, having hit a record high on Friday on supply concerns. 

"The impact of this round of power rationing on demand for refined tin is significantly greater than the impact on supply," the ITA said in a note. Producers in the tin-smelting heartland of Yunnan, which were affected by previous power restrictions, are now operating normally, it added.

Some solder companies in eastern China's Jiangsu province have already halted production ahead of a week-long holiday in China beginning Oct. 1, the ITA said, as power curbs are being "stringently enforced."

Solder capacity in Guangdong has also been severely reduced, it said, adding that tinplate producers' power supply in the southern province was being strictly controlled.

Tin chemical producers in Shandong have cut capacity by 30%-50%, it added.

In a further easing of supply tightness, recent high tin prices have prompted the authorities in Myanmar, China's biggest source of imported tin ore, to sell off their tin concentrate stocks, the ITA said.

It estimates that will put more than 5,000 tonnes of additional tin in concentrate on the market in the next few months, boosting treatment charges and potentially leading to an increase in refined tin production.

"The price of tin, which was previously supported by fundamentals, may face greater downward pressure," the ITA added.

(Reporting by Tom Daly; editing by Simon Cameron-Moore, Kirsten Donovan) ((tom.daly@thomsonreuters.com; +86 10 5669 2119;))