Mr Olsen said speed camera warning signs in school zones generally showed a 40kmh speed limit, which applies for three hours a day, but did not show the speed limit during non-school zone hours.

Mr Olsen said unsuspecting motorists were being caught speeding during non-school hours because signs including those at Forest Road at Penshurst and Hurstville; Princes Highway, Kogarah and King Georges Road, Beverly Hills did not indicate the correct speed limit on the approach.

"For example, most of King Georges Road is 70kmh. The section through Beverly Hills shopping centre is 60kmh, but the speed camera signs do not indicate that,'' Mr Olsen said. ``They are half a kilometre from schools at either end of the shopping centre they are supposed to protect.''

He said fines had a big effect on family budgets while unfair demerit points meant people using a vehicles for work could lose their jobs.

NSW Roads Minister Michael Daley announced changes this week to the demerit point system for NSW drivers that will take effect in September.

A spokeswoman for Mr Daley said NSW Roads and Traffic Authority was investigating suggestions to improve the visibility of school zones. She said NSW followed Australian standards for installing speed limit signs.

Is there a need for improvements?