Parents taking children to sports clubs regularly are affected
Plans to vet parents who take part in activities involving regular contact with children have been criticised by children's charity, the NSPCC.
Children's services director Wes Cuell told the Sunday Telegraph the move could stop people doing things that were "perfectly safe and normal".
Under the rules, millions of parents will have to undergo criminal record checks or face fines of up to £5,000.
The scheme will run in England, Wales and Northern Ireland from next month.
A separate but aligned scheme is being set up in Scotland, to be introduced next year.
The Home Office's Vetting and Barring Scheme is being extended to apply to parents including those who regularly drive children to sports or social clubs or host foreign exchange students.
Informal arrangements between parents will not be covered.
The move is designed to protect children from paedophiles, but critics claim it is threatening civil liberties and may deter volunteers.
Mr Cuell, of the NSPCC, said: "The warning signs are now out there that this scheme will stop people doing things that are perfectly safe and normal: things that they shouldn't be prevented from doing.
"When you get this degree of public outcry, there is generally a good reason for it.
"I think we are getting a bit too close to crossing the line about what is acceptable in the court of public opinion.
"We don't want to throw the baby out with the bathwater."
The Sunday Telegraph added that Mr Cuell stressed that while it was important to strengthen rules to protect children from potential sex offenders, overzealous interpretation of the regulations could threaten civil liberties.
Children's authors, including Philip Pullman and Michael Morpurgo, have complained the requirement is "insulting" and say they will stop visiting schools.
Earlier this week children's minister Delyth Morgan said safeguarding children was the government's priority and it was about ensuring people in a position of trust who work with children are safe to do so.
Teachers and doctors
The new regulations will mean anyone taking part in activities involving "frequent" or "intensive" contact with children or vulnerable adults three times in a month, every month, or once overnight, must register with the Home Office's new Independent Safeguarding Authority (ISA).
All school governors, doctors, nurses, teachers, dentists and prison officers must also sign up.
After November 2010 failure to register could lead to criminal prosecution and fine. Clubs themselves also face a £5,000 penalty for using non-vetted volunteers.
Registration will cost £64 in England and Wales, but unpaid volunteers will be exempt from the charge.
The scheme was recommended by the Bichard report into the Soham murders of Holly Wells and Jessica Chapman by college caretaker Ian Huntley.