UK labour union GMB said on Wednesday that Amazon.com's Coventry warehouse workers had voted for six more months of strike over a pay dispute, after they staged a walkout earlier in the day.

The e-commerce giant's workers at its Britain site had staged the first strike in January and followed it up with strikes in February, March and April.

Last week, GMB said the company's workers would strike between June 12 and June 14.

"The vote for six more months of strike action at Amazon Coventry shows these workers are in for the long haul," GMB's senior organiser Amanda Gearing said in a statement.

A 99% majority voted to extend the industrial action, the union added.