China's voracious appetite for commodities lifted imports of copper and iron ore to new highs in April, despite a global economic slowdown, while the world'sdemand for China's exports remained weak.

China also bagged its second-biggest monthly haul of crude oil and tripled aluminum imports in April, while very little steel, aluminum and coal went the other way.

Industrial production is coming online and demand is rising. But sentiment may be tempered by the view that some of the material is being stockpiled and... consumption hasn't risen as quickly as imports, said Ben Westmore, commodities economist at National Australia Bank.

Copper imports rose to 399,833 tonnes in April, up 6.6 percent from March, iron ore imports jumped 9.4 percent to 57 million tonnes, and crude oil imports hit 3.93 million barrels per day, a 2 percent rise, customs data showed.

The apparent demand from the domestic economy, which is being watched worldwide for signs of a revival, was offset by the slowing demand for China's exports. Aluminum shipments were down 90 percent versus April last year and steel product sales down 70 percent.

All of them are surprising figures, said a senior trading executive in a state-owned steel mill after perusing the data for steel and iron ore.

The figures show that oversupply is very likely to worsen in May and June, said the executive, who asked not to be identified as he was not authorized to speak to the media.

The problem for China's exporters -- and the icing on the cake for many a trader looking to dump an unwanted cargo -- is that China is a high-cost producer of many commodities.

As the state offers above-market prices for aluminum and soybeans and local coal and iron ore miners fail to control costs, the door has opened to trade from around the world.

The problem has been exacerbated by the sliding cost of freight, although the mass of ships bound for China has helped revitalize the freight index.

It is still unclear whether a rise in the index shows healthy demand or just that so many ships are lined up at China's ports, waiting to unload iron ore.

PATIENCE

The commodity trade numbers published by the General Administration of Customs on Tuesday showed a similar picture to the overall trade figures, which traced a steeper-than-expected fall in exports but a massive surge in investment, helped by government pump-priming and buoyant bank lending.

A month-on-month improvement showed export demand was stabilizing, although consumer demand in developed markets was likely to be structurally weak for a while, analysts at Morgan Stanley said.

Much patience could be needed before China resumes the robust growth track in trade experienced in the mid 2000s, they wrote in a note to clients.

The April monthly data was the first set of figures this year which did not suffer from the distorting effect of China's Lunar New Year holiday, a movable feast which fell in January this year, making yearly and monthly comparisons tricky.

But other events in 2008 -- notably the Sichuan earthquake and the Olympic games -- mean it will be difficult to chart China's year-on-year progress for much of this year.

April's commodities trade figures are also still partly clouded because the customs office's preliminary data left out some key numbers, to be detailed later in May when it releases a full set.

That will include a breakdown of China's trade in refined oil products, which showed a 5 percent fall in net imports during April as refineries released excess fuel into the Asian market, as well as figures for refined copper and primary aluminum.

The customs bureau also kept back the figure for April's coal imports, which analysts see rising toward 6 million tonnes thanks to a surfeit of Asian coal and the Chinese miners' failure to lock China's big power firms into annual supply contracts.

Coal exports for April stagnated in the face of cheap competition, slipping to 1.96 million tonnes, barely half the monthly average for the last 20 years.

China Crude oil