Children's Secretary Ed Balls has ordered a review of the Government's scheme to vet around 11 million adults who work with adults or vulnerable children.
Mr Balls said he wanted to look again at the scope of the Vetting and Barring scheme to make sure the "right balance" has been struck on how many people are covered.
There was outrage last week when it emerged parents who regularly give lifts to other children on behalf of clubs such as the Cub Scouts would be required to undergo criminal records and other checks.
Under current rules parents who volunteer to take part in school exchange schemes will also have to be vetted by the Independent Safeguarding Authority.
The review will be carried out by ISA chairman Sir Roger Singleton and will report by the beginning of December, said Mr Balls.
In a letter to Barry Sheerman MP, the chairman of the Commons Children, Schools and Families Select Committee, Mr Balls defended the scheme and said there was "strong support" for it among children's charities and in the voluntary sector.
He said asking people to register for vetting was "categorically not a presumption of guilt", but a "sensible and proportionate contribution to keeping children safe" and compared it to the law that requires people to wear a seatbelt. But he acknowledged "concerns" about how low the bar for contact with children was set before people were required to register.
Anyone who falls within the rules and is not cleared by the ISA before working or volunteering faces a fine of £5,000. Any organisation which uses them without checks could be fined the same amount. Registration costs £64 for those seeking employment with children or vulnerable adults but is free for volunteers.
Shadow home secretary Chris Grayling said the announcement was "not good enough" and called for a review of the "whole issue".
He said: "I'm afraid this is just not good enough. The reality is that the Government's words on this are so vague and ill-defined that no one will know where the dividing line falls. They'll look at the level of fines and register everyone to be on the safe side. The Government has to look at this whole issue again."