State Highway 25A on Coromandel Peninsula to reopen to one lane for 12 hours after cracks found

  • 17/01/2023
Numerous cracks have been found on the road.
Numerous cracks have been found on the road. Photo credit: NZTA / Getty.

A major highway used by holiday-goers will be reopened to one lane for 12 hours on Wednesday after previously being completely closed.

The Kopu-Hikuai Highway (State Highway 25A) connects the west and east sides of the Coromandel Peninsula from south of Thames to south of Tairua. It is one of the main routes for holiday-goers from Auckland heading to towns like Whitianga and Whangamatā.

But large cracks found in the road on Monday - and the "potential risk of the cracks worsening" - led Waka Kotahi NZTA to close the road. 

Geotechnical investigations took place on Tuesday to help officials decide whether the road needed to remain closed or if it could safely reopen. 

In a statement on Tuesday afternoon, NZTA said the road would reopen to one lane from 7am on Wednesday morning to 7pm on Wednesday night. It will be fully closed again overnight on Wednesday/Thursday.

"Geotechnical engineers have been on site today to assess a significant number of cracks of various lengths, some measuring 15 metres deep and up to 75mm wide. Monitoring devices are being put in place to detect deterioration. If the situation worsens, the road may have to be closed again while further solutions are investigated.

"During daytime hours, experts advise the highway is safe to open to one lane under stop/go traffic management with a temporary speed limit of 30km/h.

"Motorists will be directed to drive on the side of the pavement that is least affected. Cracks on this side are being filled this afternoon to prevent rain getting in."

Rob Campbell, regional manager for maintenance and operations, said earlier that safety is the top priority.

"The cracks have appeared following Cyclone Hale, which caused flooding and numerous slips across the Coromandel Peninsula. As there are numerous cracks we need to understand what is happening before we allow road users through this area," said Campbell.

"We can look back to August last year when cracks appeared on State Highway 35 near the Motu River in the Eastern Bay of Plenty. That situation moved rapidly, and we lost a lane to the river within days of the cracks first appearing. While that may not happen here, we cannot take any chances."

The closure means road users will need to either use State Highway 25 around the Coromandel Peninsula or State Highway 2 south and through Karangahake Gorge and Waihi.

It will mean a much longer drive for motorists.

If driving from Auckland CBD to Tairua, a trip using the now-closed highway would normally take about 1 hour and 56 minutes, according to Google Maps. However, taking SH25 around the peninsula will take 3 hours and 42 minutes. Going south on SH2 and then through Karangahake Gorge and Waihi will take 2 hours and 48 minutes, Google Maps says.