Senior roading engineer Rob Hayes said it was not just the cost or inconvenience raising alarm bells at the council, but the serious safety issue the damage was creating.
"There’s a certain percentage of the signs which have significant safety implications with them being removed, like stop signs, speed advisories, curve advisories, single-lane bridges."
Advance warning signs were important because they alerted drivers to the change in conditions, such as changing from seal to gravel.
Mr Hayes thought serious accidents had only been avoided so far because many of the drivers travelling at night were locals who were familiar with the roads.
Most people would probably regret waking up in the morning to discover their removal of the sign during the night had caused a terrible accident, he said.
Council records showed the 11,030 sign repairs made since 2019 had cost ratepayers nearly $200,000.
The figures did include wear and tear and genuine accidental damage, but the vandalism was an ongoing network-wide issue, he said.
It was the unnecessary cost within an already tight budget that was creating additional frustration with council staff.
"We suspect the vast majority is targeted vandalism."
The council frequently found series of damages in specific areas or roads.
Mr Hayes believed a large portion of the damage was happening between Thursday and Saturday evenings across the network.
While the vandalism problem was not a new one, the increase in recent months was starting to clock up a huge repair cost for the council.
Te Anau township street signs were also recently vandalised.
Overseeing 4961 km of roads, the council managed the second-largest overall roading network in the country and the largest unsealed road network.
Staff were immediately sent to all safety-related sign damage, which incurred further costs for the council.
The vandalism has been reported to the police.
Southern district road policing manager Inspector James Ure said anyone caught willfully damaging the road signs would probably be charged.
"Should there be a serious injury or fatal crash as a result, persons responsible for damaging those safety signs we would expect to thoroughly investigate."
— Crimestoppers 0800 555 111.
By: Toni McDonald
