Understanding why children bring knives into school is better than a blanket exclusion policy, the chief inspector of Welsh education inspectorate Estyn has said.
Owen Evans said the "easy answer" was to ban or exclude but he believed there needed to be more nuance.
He said there were multiple reasons why a child might bring a knife into school and a one-size-fits-all policy would not work.
But the NASUWT union's national officer for Wales, Neil Butler, described the suggestions as "most unhelpful" and said immediate exclusions needed to be a priority to keep everyone safe.