Three-month copper on the London Metal Exchange hit $6,173 a ton, the highest since March 26 before going into the red and falling 0.7% to $6,010 a ton in official midday trading.
China easing, though more aggressive than expected, had been expected and so was already priced in to an extent.
"The reaction so far is relatively modest, there has been speculation for some time about more easing in China," said Jens Pederson, analyst at Danske Bank. "There is some concern China may allow its currency to weaken, which could have a short-term negative effect on base metals."
Also weighing on the metals market was a firmer dollar. A stronger dollar is typically a negative for commodities because it makes them more expensive for investors holding other currencies.
Expectations of a narrower copper market surplus due to mine disruptions have also helped boost sentiment
China's central bank boosted banks' lending power by cutting the amount they must hold as reserves, but the local property market is still a major concern.
"All the moves to date really haven't worked at stabilizing the property market, which is what we need for metals," said analyst Dan Morgan at UBS.
Three-month tin failed to trade in official rings and was bid up 1.4% at $15,050 a ton. Last week the metal used in electronic components tumbled to $13,600, its lowest since September 2009 on concerns about a supply glut.
"The drop last week was overdone, there's probably been some profit-taking, but we won't know how much until we have more recent positions data," a trader said.
Latest data shows short tin positions on the LME amounted to 22,595 tons, while total open interest stood at 22,990 lots.
Three-month zinc climbed to a session peak of $2,248 a ton, the highest since Dec. 5, and added 0.6% to $2,226 in official trading.
Expectations of a zinc market deficit and falling stocks in LME registered warehouses—at 492,575 tons, down more than 30% since September 2014—are behind higher prices.
Battery material lead has also been helped by falling LME stocks, which at 200,200 tons have fallen more than 15% over the last four weeks.