The education secretary told MPs that there is a “disparity” across the sector around the length of the school day, adding that it is “an important issue with so much catching up still to do”.
Speaking in the Commons, Mr Williamson questioned whether it was “justifiable that some schools send their children home at 2.45pm, where others keep them in much longer”.
He added that “too many schools” have restricted what children can do in their breaks, as a lunch hour is increasingly becoming “a school lunch half hour”.
His comments came after the education recovery commissioner quit on Wednesday, with a condemnation of the Government’s £1.4 billion catch-up fund, which he said fell “far short” of what was needed.
Catch-up tsar Sir Kevan Collins had recommended that schools and colleges should be funded for a flexible extension to school time – the equivalent of 30 minutes extra every day.
But the Government’s latest announcement did not include plans to lengthen the school day.
Addressing MPs in the Commons on Monday, Mr Williamson thanked Sir Kevan for “his contribution to these efforts” following his departure.
He added that the Government continues to “pledge significant packages of investment” to help pupils catch up on education missed due to the pandemic.
Mr Williamson told MPs: “As we move forward over the next few months, there are significant challenges as we talk about the school day.
“We’ve seen too many schools go down a route of actually restricting what children have the benefit of doing.
“A school lunch hour has become increasingly restricted and is increasingly a school lunch half hour as against an hour.
“So what we’re wanting to do is ensure that as we do this review we look at all the options, so children are not able to just benefit from better academic attainment with extra support in English and maths, but also enrichment in the other activities they can benefit from being in school.”
But Daisy Cooper, the Liberal Democrats’ education spokeswoman, accused Mr Williamson of “presiding over nothing but blunders” as she asked if “the right man resigned”.
She asked: “Sir Kevan Collins has a distinguished 30-year career as an expert in education whilst the secretary of state has spent 18 months presiding over nothing but blunders, putting the future of our young people at risk.
“So does the secretary of state think that the right man resigned?”
Shadow education secretary Kate Green said Mr Williamson’s “lack of vision and ambition” with the catch-up proposals had “let down” young people.
She told MPs: “The Government failed children and young people.
“They were promised that their education was the Prime Minister’s number one priority but they’ve been betrayed by a secretary of state who has let them down once again, and by a Prime Minister who won’t lift a finger for them when it comes to a row with the Chancellor about prioritising the investment needed in their future.”
Responding to a private notice question on the issue in the Lords on Monday, education minister Baroness Berridge said more than £3 billion has been committed so far, before adding: “We will consider the next steps ahead of the spending review and catch-up is for the lifetime of this Parliament.”
But Labour education spokesman Lord Watson of Invergowrie said:
“I can’t really believe the minister is comfortable defending the indefensible following the chaotic events surrounding the Government’s, what can only be described as a bargain basement recovery plan for school pupils.”