Road sign changes in the district is costing about $25,000.
The district council is currently changing speed limits in the area as part of its speed limit review, which took place at the end of last year.
Speed limits have dropped from 100km/h to 80km/h on many roads and from 70 to 60km/h and 70 to 50km/h on others.
The changes are being made because of the urban growth in townships across the district.
District council asset engineer transportation Mark Chamberlain said it does not have “an actual cost of the installation” just an estimate.
Last month, some motorists were confused when Birchs Rd had both an 80km/h and 100km/h sign on display. The signs have now been all changed to 80km/h.
Police say they are applying a “common sense approach” to the changes when it comes to enforcement.
Senior Sergeant Pete Stills agreed there had been some “ambiguity” with some of the changes.
“Signage hasn’t always changed quickly or signs in one direction might be different to signs in another direction,” he said.
Meanwhile, in August, there will be a combined review of both Selwyn’s speed limit bylaw and speed limits outside schools.
The district council decided to combine the reviews to prevent confusing the public after concerns it may be over consulting on speed limit-related issues.