Schools secretary Ed Balls has pledged to ease rules on vetting adults who work with children.
A report carried out by the government's chief child safety adviser, Sir Roger Singleton, accepted that the scheme had been too restrictive.
Rules requiring adults to undergo criminal records checks before being allowed to volunteer in schools had provoked protests from leading children's authors including Philip Pullman.
The U-turn has been welcomed by children's groups and headteachers as a "pragmatic" approach.
Adults are now to only be vetted if they meet with the same group of children or vulnerable people more than once a week, rather than once a month.
The children's secretary said around two million adults will no longer be affected by the rules.
Speaking on GMTV, Balls said arrangements between parents such as the school run had never been part of the Vetting and Barring Scheme (VBS), but unchecked volunteers could not be allowed to look after children.
He said changes to the system would give a better balance between safety and unnecessary checks.
Key recommendations in the report included a call for immediate changes to the rules so that 16, 17 and 18-years-olds in education are not required to register.
Sir Roger told BBC Radio 4's Today programme that at the time legislation at been framed three years ago, politicians had been "very concerned to close down every possible loophole".
"The atmosphere now is different. It is one looking for more balance and proportionality," he added.
"What I have done is looked very carefully at the evidence we have got about the circumstances in which adults abuse children with whom they have a responsibility and a position of trust, and I felt that the numbers of cases that would fall within this sort of category was so small that it was justifiable to actually make the reduction."
