Education Secretary Michael Gove told ITV News there is "no excuse" for teachers going on strike, which has "caused disruption for hardworking parents".
Mr Gove said: "There's no justification for this action and teachers, I hope, will draw the appropriate lesson from today which is that it is their responsibility to put children first and to be in the classroom teaching, not on the picket line striking."
Public sector workers in Britain have gone on strike today in a row over pay, pensions, conditions, jobs and spending cuts.
Public sector workers are striking today over a row on pay, conditions, pensions and spending cuts.
Here are some of the reactions from Twitter users on the industrial action.
I'm with the strikers. No pay rise for years while ministers give themselves 11% + expenses? Unacceptable #strikeaction
As a parent I would be happy if my children couldn't go to school, they are teaching kids to stand up for what's important #strikeaction
Britain's top earners should "contribute a little bit more" so public sector workers can have "decent pay", the head of a trade union told Good Morning Britain.
Dave Prentis dismissed Francis Maude's claims the Government could not afford a pay rise and said, "the top 1% have increased their wealth by 18% in the last year - can't just we ask that they contribute a little bit more, via the taxation system, to enable us to have decent pay?"
If public sector workers are given a bigger pay rise than the 1% promised by the Government, it will lead to "debts ever larger for our children and our grandchildren to have to pay off", a senior minister said.
Francis Maude told Good Morning Britain "pay restraint is essential" if the UK ever wants to get its deficit down.
David Cameron said the "time had come" to tighten strike laws and vowed to include this measure in the Conservative manifesto ahead of next year's General Election.
The Prime Minister attacked low turnouts in some ballots, pointing out that only 27% voted on whether to strike in a 2012 walkout.
During his weekly questions in the Commons, he said: "I don't think these strikes are right...I think people should turn up for work.
"I think the time has come for looking at setting thresholds in strike ballots... The (NUT) strike ballot took place in 2012, based on a 27% turnout.
"How can it possibly be right for our children's education to be disrupted by trade unions acting in that way? It is time to legislate and it will be in the Conservative manifesto."
The Government says it is expecting most schools to open and most public sector workers to stay at work during Thursday's industrial action.
A spokesperson for the Cabinet Office said: “The vast majority of dedicated public sector workers did not vote for today’s action, and early indications are that most are turning up for work as usual.
“We have rigorous contingency plans in place, services appear to be working well. and we expect most schools and job centres to open their doors."
“It is disappointing that, once again, some union leaders have pushed for strike action that will achieve nothing and benefit no one. Union leaders have relied on mandates for action that lack authority – the National Union of Teachers ballot was run nearly two years ago, while other ballots had extremely low turnouts.”