Chinese tax authorities are expected to audit all domestic gold traders as part of a clamp down on the unscrupulous practice of using a fake precious metals trade to disguise capital flows.
Net inbound shipments into mainland China fell to 4.6 metric tonnes in April from a March figure of 61.8 tonnes, with mainland buyers purchasing 55.2 tonnes last month compared to 72.1 tonnes a month earlier.
Signs of increased housing demand in the US allowed copper to break its five week slump, with previously owned home sales exceeding economists' expectations in April.
The pick-up in residential estimates will contribute to the country's economic growth.
The London Metals Exchange registered copper-for-delivery settling at $US6095 ($A7965) per metric tonne, a 0.2% increase in three months.