The old Kōpaki rail overbridge on SH30, south of Te Kūiti, will permanently close to all vehicles from Friday 9 December due to the increasing risk the bridge will collapse.

The timber bridge has been under a six-tonne weight limit since late 2021, however Waka Kotahi said repeated breaches of this restriction have accelerated the bridge’s deterioration.

The replacement bridge is expected to be completed in April next year.

In the meantime, all traffic between Te Kūiti and Maniaiti/Benneydale will need to use SH3, SH4 and Kōpaki Road.

“We were hoping the old bridge would remain open to light vehicles until the new one is complete, but unfortunately the risk of a collapse has become too great, especially given the size of some of the vehicles we’ve seen crossing the bridge,” said Waka Kotahi NZ Transport Agency regional manager maintenance and operations, Rob Campbell.

“We’ve investigated various options for keeping the bridge open, such as installing barriers to restrict higher vehicles, however none of these would provide a safe solution that would guarantee that heavy vehicles could not access the bridge.

“The only option that can guarantee the safety of SH30 traffic is to close the bridge,” he said.

“This is going to be inconvenient for the local community for the next five months and we apologise for this, however safety is our priority.”

Campbell said as the bridge crosses the North Island Main Trunk rail line, which includes a 25kV overhead line, the consequences of a bridge collapse are even more serious, and especially so if it occurred when a train was passing underneath.

“We’ve given a week’s notice so that the community has time to prepare for this. We would remind the drivers of heavy vehicles that the six-tonne limit remain in place until the bridge closes,” he said.

From Friday 9 December barriers will be installed to prevent access to the bridge. The detour of SH3, SH4 and Kōpaki Road adds around 12km to the trip between Te Kūiti and Maniaiti/Benneydale.