Updates prices as of 0821 GMT

BEIJING, March 20 (Reuters) -Nickel and tin prices in Shanghai declined on Wednesday, as investors eyed more mining output from main producer Indonesia after the country said it will accelerate its approval process.

The most-traded May nickel contract on the Shanghai Futures Exchange (SHFE) SCFcv1 closed day-time trade 2% lower to a nearly two-week low at 136,450 yuan ($18,953.23) per metric ton.

The most-traded April tin contract SCFcv1 fell 2.6% to 224,430 yuan per ton, after dropping as much as 3% - the biggest loss in three months - earlier in the session.

Prices of the metals in London fell on Tuesday after a senior Indonesian mining ministry official said the country had issued production quotas of 152.62 million tons of nickel ore and 44,481.63 tons of tin so far this year, and was working to accelerate the approval process.

The delayed issuance had sparked fears of supply tightness, supporting prices over the past few months.

"Signs of faster approval and better supply offset recently improved demand supported by better stainless steel production," Hongyuan Futures analysts noted.

Nickel, a key metal for stainless steel and battery production, is plagued by a global supply glut. An executive at Vale VALE3.SA said on Tuesday the market would swing to a deficit by 2028.

Three-month nickel on the London Metal Exchange CMNI3 rebounded 0.4% to $17,465 per ton by 0821 GMT, while LME tin CMSN3 was down 0.3% at $27,365 per ton.

Investors now focus on the U.S. Federal Reserve's monetary policy decision later in the day for further clues about the timing and quantum of interest rate cuts.

LME copper CMCU3 lost 0.5% to $8,934 per ton, aluminium CMAL3 ticked up 0.1% at $2,271, zinc CMZN dipped 0.1% at $2,502, and lead CMPB3 shed 0.6% to $2,081.50.

SHFE copper SCFcv1 slid 0.9% to 72,620 yuan per ton, zinc SZNcv1 shed 0.4% to 21,195 yuan, aluminium SAFcv1 nudged 0.1% lower at 19,285 yuan, while lead SPBcv1 climbed 0.1% to 16,255 yuan.

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($1 = 7.1993 Chinese yuan)

Reporting by Siyi Liu and Mei Mei Chu; Editing by Subhranshu Sahu, Varun H K and Sherry Jacob-Phillips

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