LONDON: Aluminium prices advanced to their highest in nearly two years on Tuesday as speculators bought on expectations of further tightness in China, which would only be partly offset by higher output in the top producer and consumer.

Benchmark aluminium on the London Metal Exchange (LME) rose 0.5% to $1,961 a tonne by 1250 GMT, after touching a December 2018 high of $1,972.

LME prices for the metal used in aerospace industry and canned goods have climbed about a third since March while prices on the Shanghai Futures Exchange are at three-year highs.

But analysts said the rally could be overdone.

"The fact that China became a net importer of metals was a valid driver for prices to bottom but the price has skyrocketed since March," said Gianclaudio Torlizzi, a partner at consultancy T-Commodity in Milan.

"At current prices Chinese smelters are making good money and they will increase production."

DEMAND: Analysts at UBS said in a note that China's apparent demand is up 15% year-to-date with strong end-user demand from UHV cable, automotive, photovoltaic and appliances.

"The global aluminium market is oversupplied in 2020 but there is currently genuine tightness in China which is driving the recent price strength."

The consensus forecast in a Reuters survey of analysts showed the aluminium market in surplus by about two million tonnes this year.

CHINA OUTPUT: China, the world's top aluminium maker, churned out a monthly record of 3.2 million tonnes in October, up 9.7% from a year earlier, as new smelting capacity ramped up to cash in on strong prices.

POSITIONING: Speculators remained bullish on rising LME aluminium prices with the net long position reaching 4.9% of open interest as of Friday's close, estimates by brokers Marex Spectron showed.

This was close to a multi-year high of 6.6% touched on Oct 19, the broker said.

PRICES: LME copper fell 0.4% to $7,077.50 per tonne, zinc shed 0.1% to $2,677, lead added 0.5% to $1,923, tin rose 0.7% to $18,900 while nickel eased 0.8% to $15,768.