US crude oil inventories surged last week to another record high, while gasoline stocks went the other direction, posting their largest one-week drop in nearly six years, the Energy Information Administration said.

Brent crude dropped 3.1 per cent to $US54.18 a barrel at midday in New York, according to Bloomberg. US oil shed 3.4 per cent to $US51.35 a barrel.

Crude inventories rose 8.2 million barrels in the week to March 3, compared with analysts' expectations for a 2 million-barrel build. Most of that - 4.6 million barrels - came from an unexpectedly large surge in stocks on the west coast.

The ninth weekly crude build boosted total stockpiles, excluding the nation's strategic petroleum reserves, to a fresh record of 528.4 million barrels.

Crude stocks at the Cushing, Oklahoma, delivery hub for US crude futures also rose 867,000 barrels, the EIA said.

On the other side of the refining equation, gasoline posted its biggest weekly inventory drawdown since April 2011, with a 6.6 million-barrel drop, owing to strong nationwide demand and reduced refining output on the US East Coast.

Analysts in a Reuters poll had forecast a 1.4 million-barrel drop in gasoline stocks.

"Crude stocks were bolstered by rebounding imports, while both gasoline and distillates draws were exacerbated by higher implied demand," said Matt Smith, director of commodity research at ClipperData.

US crude imports rose last week by 385,000 barrels per day.

Refinery crude runs slipped by 172,000 bpd as utilisation rates edged down 0.1 percentage point to 85.9 percent of total capacity, EIA data showed.

Distillate stockpiles, which include diesel and heating oil, fell by 2.7 million barrels, three times more than forecast.