The US trade deficit soared in August as surging Chinese imports worsened global economic imbalances and stoked rising American anger with China's exchange rate policy.

The data, published on Thursday, come ahead of Friday's release deadline for the US Treasury's twice-yearly report on exchange rates, in which it has to decide whether or not formally to name China as a currency manipulator.

The figures released by the commerce department showed the deficit in goods and services widening by 8.7 per cent to $46.3bn.

Despite congressional pressure, the Treasury has so far refrained from using the label, arguing that it makes no practical difference to relations with Beijing.

Exports ticked up by 0.22 per cent to $153.8bn, the highest level in two years, but were outstripped by imports, which jumped by 2.1 per cent to $200.2bn.

That figure was the second highest gap of the year, exceeding economists' expectations.

The rise was driven by US businesses stocking up on consumer goods and cars at the end of summer.

In August, imports from China rose by 6.1 per cent to a record $35.3bn.

That left a US trade shortfall with its most politically sensitive trading partner at a record $28bn at a time when the US is intensifying its scrutiny of China for creating trade imbalances by undervaluing the renminbi.

"The structural US trade deficit continues to persist on the lack of Chinese demand for US exports," said Michael Woolfolk, analyst, BNY Mellon Global Markets.

Ian Shepherdson, chief US economist at High Frequency Economics, notes that much of the expansion of the deficit in August was due to rising oil prices and a drop in aircraft orders.

Economists expect imports to the US to cool as the end of the year nears because consumer demand remains tepid.

The US deficit with China accounts for about half of its shortfall with the rest of the world. US deficits with the European Union, Canada and Japan also widened in August.