Airport-style X-ray machines would be introduced into schools if it was the only way to tackle knife-carrying, said the education secretary.
There are plans for spot checks for weapons
Charles Clarke told BBC1's Breakfast with Frost he hoped it would never come to it, but said the priority was to eradicate the weapons from schools.
"There are too many tragedies that happen because children have brought knives into schools," he said.
New plans on discipline in English schools were revealed last week.
Schools could be given powers to search pupils for weapons, under plans to tackle bad behaviour, Mr Clarke said.
The minister told Breakfast with Frost on Sunday that Metropolitan Police commissioner Sir John Stevens had recently expressed support for X-ray machines in "certain places".
"Our number one requirement is that there should be no knives in schools full-stop," said Mr Clarke.
"I can't see any circumstances in which it can ever be justified for a child to have a knife in school. Whatever steps are necessary to deal with that need to be taken," he added.
On Thursday Mr Clarke also talked of encouraging schools to arrange for surprise police searches of their premises.
And all schools are to be told to take their share of excluded pupils to stop disruptive children being concentrated in so called "sink-schools".
The Department for Education and Skills (DfES) is supporting Home office moves to raise the age at which knives can legally be bought from 16 - possibly to 18.
In November 2003, 14-year-old Luke Walmsley was stabbed to death at the Birkbeck School in North Somercotes, Lincolnshire, by a fellow student.
His mother Jayne is campaigning for tougher sentences for those caught with knives.
The National Association of Head Teachers has backed the government's stance, saying there should be "zero tolerance" of knives and other offensive weapons, with more back-up from the police for schools.