WASHINGTON (AFP) - The US trade deficit swelled in March to a six-year high on a surge in imports from the end of the West Coast port strike backed by the strong dollar.

The trade gap was US$51.4 billion (S$68 billion) in March, jumping from a slightly upwardly revised US$35.9 billion in February, the Commerce Department said Tuesday.

The March deficit was the highest since October 2008 amid the financial crisis. The increase from February far exceeded the average analyst estimate of a $40.0 billion deficit and was the largest monthly gain since late 1996.

Imports surged to US$239.2 billion in March from US$222.1 billion in February, while exports edged up to US$187.8 billion from US$186.2 billion.

The end of the West Coast port strike in late February, in a deal between management and dock workers, unleashed a flood of imports that had been backed up in the months-long work slowdown, Commerce Department data showed.

The economy imported a record US$54.2 billion in consumer goods in March, the department highlighted, as the strong dollar underpinned buying power.

Robust US crude oil production pushed the country's trade surplus with the countries of the OPEC oil cartel to a record US$1.2 billion.