Parent groups fear drivers may ignore new rules on children's car-seats.

From Monday, motorists face £30 on-the-spot fines if young passengers do not have the correct seat or booster cushion.

But Jo Gurr, coordinator of the Single Parent Information Network (Spin), based at Ditchling Rise, Brighton, says not enough has been done to inform the public of the changes.

She said: "I don't think it's filtered through. A lot of people are fairly incredulous and plan to ignore it."

New EU rules mean children under three must have the correct baby or child seat, while children under 4ft 5in (135cm) or under 12 must have booster seats or special cushions.

The Department for Transport says that without restrictions children in seatbelts designed for adults may slip out or suffer internal injuries in an accident because of their different size and bone structure.

Lorraine Steele, of Fairlight Primary School's parent-teacher association, said she thinks it is "highly unlikely" parents will be ready for the change.

She said: "I don't think they've given enough publicity. It's a good idea and could save lives but I don't think they've given enough information."

At Spin, Ms Gurr said she welcomes the tighter laws on car-seats.

She said: "Being an ex-police officer who has seen a lot of accidents, I feel strongly children should be secured in their seats.

"People are fairly good from birth to 12 months but when children become toddlers they object to it and parents give in."

Superintendent Paul Morrison, of Sussex Police, said: "The new laws are designed to save lives and prevent injury.

"Parents and childcarers will see the laws as guidance on the safest method to transport children. Those who ignore the law may put the child's life at risk and also risk being prosecuted."

Penalties for offenders are a £30 fixed penalty or a maximum fine of £500 if a case goes to court.

Senior police officers are discussing whether to start issuing fines on September 18 or have a period where drivers are simply warned they are breaking the law.

Motorists making a short emergency journey are exempt from the law as are licensed taxis.

Seats and booster cushions are available from major stores.

For more information, see www.thinkroadsafety.gov.uk or call 0800 327252 for a leaflet.