Copper prices on Tuesday hovered a little above last week's six-month low as investors braced for Chinese data that is expected to show a further contraction in factory activity.

Benchmark copper on the London Metal Exchange (LME) was up 0.1% at $8,141 a tonne in official trading having gone as low as $7,867 on May 24.

The metal, used in the power and construction industries, is down 15% from a high in January due to a weaker than expected economic recovery in China and slowdowns elsewhere.

Helping copper on Tuesday was the first weakening of the U.S. dollar since May 19, which made dollar-priced metals cheaper for buyers with other currencies.

But the outlook for demand remains bleak.

Analysts expect China's official manufacturing Purchasing Managers' Index (PMI) on Wednesday to show contraction for a second consecutive month in May.

China's construction industry is stagnant, Chinese Yangshan copper import premiums at $37.50 a tonne are stuck well below their long term average, and copper stocks in LME warehouses have almost doubled since mid-April to 100,000 tonnes.

"We've done a full circle of pricing in China hopes and then pricing them out again as the market realised that China's recovery is very metals light and its property market woes won't go away," said Julius Baer analyst Carsten Menke.

Analysts at UBS said copper could test support levels around $7,000 if physical demand signals deteriorate further, supply improves or wider markets become more risk averse.

"We see a modest surplus in 2023 but expect a tighter market in 2024 and believe the prospect of copper moving into a more protracted deficit from 2025 increases the risk of violent price upside in the next 2-3 years," they said.

In other metals, LME aluminium was down 0.6% at $2,224 a tonne, zinc fell 0.2% to $2,340, nickel rose 1.6% to 21,490, lead slipped 0.4% to $2,071 and tin was up 1.8% at $25,300.

(Reporting by Peter Hobson; Additional reporting by Mai Nguyen in Hanoi; Editing by Conor Humphries)