A union has described the Cabinet Office's figures on the amount of people striking today as "laughable".
The Cabinet Office claims a fifth of civil servants - around 90,000 people - are on strike compared with a third in the last big walkout in 2011.
However, the Public and Commercial Services union dismissed the Cabinet Office's claims, saying: "No-one can trust this government to keep reliable figures, it can't even tell us what it's done with dozens of Home Office files."
Cabinet Office Minister Francis Maude said fewer than 20% of civil servants were on strike today compared with a third in the last big walkout in 2011.
Mr Maude said today's disruption was the fault of union leaders and urged public sector workers that the right to strike must be exercised "responsibly".
He pointed out that only one in five members of Unite and Unison had taken part in ballots leading to the strike, adding that low turnouts strengthened the case for reform.
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.