The Automobile Association says police are sending the wrong message by targeting drivers who creep slightly above the speed limit.
Motorists have been warned that anyone caught driving at more than four kilometres an hour above the speed limit during Queen's Birthday weekend will be ticketed.
But the AA says that that will punish safe drivers. It says police should be focusing only on speed if drivers are going dangerously fast or very slow.
It also says that the policy should not apply to passing areas, because, it says, it is useful to have the ability to pass other cars and get out of the line of oncoming traffic quickly.
A tolerance of 10km/h over the limit outside city areas is normally allowed.
The AA says there is too much emphasis on messages about speeding and drink-driving, at the expense of other motoring problems like driver tiredness.