Amazon.com Inc on Wednesday raised the minimum starting pay for its employees at the UK operations to between 11 pounds ($13.50) and 12 pounds per hour.
The move comes after workers at an Amazon warehouse in Coventry, central England, had struck work for several days in a dispute over pay earlier this year.
The increase will depend on locations and start from April, the company said.
"We're listening to Amazon workers and the message is very clear: this new pay rate is an insult," said Amanda Gearing, senior organiser of GMB, the union which represent more than 500 Amazon workers.
"So, in response we will be consulting over the next few days and announcing a new wave of action."
The union had said the Amazon Coventry workers are demanding 15 pounds an hour to cope with a cost-of-living crisis that has sparked strikes across sectors in Britain over the last few months.
Amazon increased starting pay by 50 pence to a minimum of between 10.50 and 11.45 pounds per hour last year.
The UK National Living Wage - a minimum wage rate which does not apply to apprentices or workers aged under 23 - is set to rise by 9.7% at the start of April to 10.42 pounds an hour.
($1 = 0.8151 pounds)
(Reporting by Yadarisa Shabong in Bengaluru; Editing by Arun Koyyur)