Council communications team leader Chris Chilton said the council had made multiple attempts to install gantry barriers since September 2019 to limit bridge access to light traffic only.
But the barriers had been continually illegally removed and signage ignored.
It appeared heavy vehicles had still been using the bridge despite the barriers and clear signage which stated weight and speed limits on the one-way structure.
"We placed signage and cones at each end of the bridge to warn people of the risks and telling them not to use the bridge, but these were all removed and/or stolen. We then had to place heavy concrete blocks at each end of the bridge to stop people driving across."
Following an independent engineer’s inspection, the council was advised that without the gantry barriers, the bridge posed a significant risk to public safety and the road needed to be closed.
"The bridge is not in great condition at all. There’s all sorts of structural issues with it, which is why the weight limits were imposed in the first place," Mr Chilton said.
Council senior roading engineer Rob Hayes said the council accepted the bridge was nearing the end of its life.
The council had hoped to maintain light commuting traffic, but additional damage to the bridge had now made the route too high risk for even light traffic.
"It’s just old. It’s got a broken pile and other structural aspects such as bracing concerns.
"The worst-case scenario would be for the bridge to fail if a large vehicle was to create significant structural damage."
The Makarewa riverbed was prone to scouring, leaving the bridge inadequately supported.
It was temporarily closed in January 2021 after a flooding event.
The gantries and sign advising "light vehicles only" on the bridge had been in place since 2019.
Anyone now attempting to use the bridge or removing the safety barriers were seriously putting people at risk.
Repairs or replacement to the structure was not on any council programme at present as staff were still discussing options.
Last year, Mr Hayes said road sign damage around the province was causing the council deep concern.
Signage and barrier damage created some serious health and safety issues.
"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."
Warning signs were important because they alerted drivers to the change of conditions.
Council records showed the 1030 sign repairs made since 2019 had cost ratepayers nearly $200,000.
Mr Chilton said because of the extensive volume of sign vandalism, it was not practical to report the issue to police he and expected police did not have the resources to help.
A detour, "which is an insignificant diversion", was available on Winton-Hedgehope highway (State Highway 96), Sharks Tooth Rd and Springhills-Tussock Creek Rd.
Written by Toni McDonald and Justine Price
