January is traditionally a strong month for copper production in China, while favourable economics also provided a boost.

China's shift to net exporter of both metals is a rare inversion of historical trade patterns.

Inventories in warehouses registered with the Shanghai Futures Exchange have more than doubled over the last two weeks.

"Iron ore is facing pressure from price control, so pay attention to policy risks," Sinosteel analysts said.

Iron ore and steel prices in China hit multi-month highs in January as markets rallied from early November.

Aluminum, and items made from the metal, now join cotton, tomatoes and polysilicon, in coming under scrutiny over links to forced labor in Xinjiang.

“We believe that the early January direction is correct but that the timing is slightly off,” said Saxo Bank.

Analysts are cautious that China's recovery may not live up to bullish expectations and that prices have got ahead of themselves.