A road in Waihi will remain closed for several days after a large tomo, which caved in underneath the road last night, leaving a hole about 1.8m wide at the surface and extending 4m - 5m deep under the road.

The tomo was discovered by a local contractor transporting farm machinery.

The area was immediately coned off and manned by locals until Council staff arrived to officially close the road and safely secure the site.

Deputy Mayor Toby Adams, who is also Council's roading and transport portfolio holder, visited the site this morning to check on progress.

'I'd really like to acknowledge the speed at which both the community and Council staff responded to this incident to ensure no one was at risk at any point. It was dark at the time, but thankfully no one was hurt due to the quick reactions of all involved."

Investigations are now underway to determine the cause of the collapse and plan remedial work.

Hauraki District Council Group Manager Engineering Services Adrian de Laborde says a series of tomos have been found on both sides of the road, as well as the one beneath it.

'Water has run beneath the culvert and formed an underground watercourse that has caused these tomos over time. Recent heavy rain in the area has exacerbated the problem."

He says work is continuing to determine the direction and extent of the underground flow of water and a bigger culvert will be installed and realigned over the next few days to prevent a recurrence of the problem.

'We're aware this road is often used as a shortcut between Tauranga and Whiritoa. Unfortunately, it's unlikely it will be reopened this week.

"We apologise for any inconvenience and thank motorists and local residents for their patience while remedial work is carried out.”