LONDON - Copper struggled to eke out gains on Tuesday as investors, many of whom believe demand for the metal will rise, worried about the outlook for global economic growth after a sharp increase in oil prices.

A surprise output target cut by OPEC+ over the weekend threatens to cause a flare-up in inflation at a time when growth in many countries is weak.

Benchmark copper on the London Metal Exchange was up 0.2% at $8,930 a tonne in official ring trading, but had fallen to $8,873.50 by 1255 GMT.

Chinese markets were closed until Thursday morning for a public holiday

Copper has risen from a low of $6,955 last July as top consumer China abandoned its economically damaging COVID-19 restrictions, but rising interest rates and concerns over the global economy and bank lending have pushed prices from January's high of $9,550.50.

"Improving Chinese demand is likely to be countered by credit concerns in the U.S. and Europe, strong mine supply and ramping Chinese refined copper output," said analysts at BNP Paribas.

"We expect limited price upside in H2 2023," they said.

While better than last year, Chinese demand has not risen as strongly as many analysts expected.

Analysts at Guotai Junan Futures said orders by China's State Grid had failed to meet expectations and new orders in the solar industry and for wire and cable had contracted.

Many analysts and investors remain bullish, however.

"Rising demand (for copper) from electrical vehicles, renewable power generation and energy storage and transmission is already offsetting the property slowdown in China... and an economic slowdown in the West," said Saxo Bank strategist Ole Hansen.

He predicted prices would rise to record highs above $10,845 in the second half of 2023. "The prospect for an increasingly tight copper market in the years to come will be the driver," he said.

In other metals, LME aluminium was down 0.2% at $2,393 a tonne in official rings, zinc fell 0.9% to $2,873, nickel slipped 0.5% to $23,260, lead rose 0.1% to $2,117 and tin was down 1.8% at $25,575.

(Reporting by Peter Hobson, Additional reporting by Siyi Liu and Dominique Patton; Editing by Shailesh Kuber)