China's refined copper output was flat in March though it should rise in April on increased smelter capacity and as fast economic growth spurs demand by the world's top industrial metals consumer.

Refined copper output reached 358,000 tons in March, data released Thursday showed, flat from a 4.1 percent rise in February as smelters cut purchases of spot concentrates on high prices and tight scrap supply, analysts said.

But China is expected to add 210,000 tons of smelting capacity this year to total 3.52 million tons by December, said Yang Changhua, copper analyst at State-backed research group Antaike, which should lead to steady increases this year.

"April's output should rise as capacity rises," Yang said, adding that Antaike estimated higher refined copper production figures in March of 380,000 tons.

"Copper production in March was likely affected by a tight supply of concentrates," said Heng Kun, chief equities analyst at Essence Securities.

Other base metals such as aluminum showed gains in March, boosted by economic growth that accelerated 11.9 percent in the first quarter, the fastest pace since 2007, driven by massive bank-financed stimulus.

However, concern that the fast economic growth would cause Beijing to further tighten monetary policy and dampen demand for metals was allayed by other headline economic data Thursday that showed consumer prices rose 2.4 percent in March from a year earlier, less than expected.