This Thursday's strike action "will achieve nothing and benefit no one" and has been carried out on a flimsy mandate, the Government has said.
A Cabinet Office spokesperson said:
The vast majority of dedicated public sector workers have not voted for this week’s strike action, so it is disappointing the leadership of the unions are pushing for a strike that will achieve nothing and benefit no one.
Union leaders are relying on mandates for action that lack authority – the National Union of Teachers is relying on a ballot run nearly two years ago. As part of our long-term economic plan, this Government has been taking tough decisions to address the deficit we inherited in 2010.
One was to introduce pay restraint in the public sector, while protecting the lowest paid.
Union leaders said they were "overwhelmed" by support after a strike by public sector workers caused widespread disruption.
David Cameron, Michael Gove and other Government figures depicted in a variety of unflattering manners by striking public sector workers.
Hundreds of schools are to close tomorrow as teachers join strike action. Find out what schools in your area are affected.