They will take action on the last two days of the month.
HM Revenue and Customs workers are to strike on the last two days of the month in a dispute over pay.
The Public and Commercial Services union (PCS) said its members employed by a private firm at HMRC will walk out days before the self-assessment online tax return deadline.
The union said more than 300 workers employed by Fujitsu Services UK at offices across the UK have been offered a pay rise of 1.5% while their in-house colleagues received 5% for doing similar jobs.
PCS general secretary Fran Heathcote said: “There is no excuse for workers employed by Fujitsu being offered less than those employed directly by HMRC.
“If the Government was serious about its pre-election pledge to bring in the ‘biggest wave of insourcing in a generation’ now is the chance to end the scandal of a two-tier workforce.
“It’s not too late for ministers to step in, resolve the pay issue and prevent strike action likely to play havoc with people’s tax returns.”
