Geothermal steam has burst through a busy Rotorua road, spewing mud and gas into the air.
The steam event erupted through a traffic island on Lake Road on Wednesday, causing traffic delays and minor flooding.
Photos from the scene show a large pond of muddy water blocking much of the road. Lake Road is near the geothermally active Kuirau Park.
Rotorua Lakes Council geothermal inspector Peter Brownbridge said the cause of fumarole (steam-driven event) is unknown at this stage.
Brownbridge said the area is not known for fumaroles and there haven't been any previous reports of hot springs in that location.
"The fumarole is not particularly large, it popped up amongst plantings in the middle of a traffic island, but there's a fair bit of water and mud on the road on the side going into town so we've closed that off for now," he said.
Brownbridge said it's not clear if a crack, that has appeared across both lanes, was caused by the steam.
"We're not detecting any heat or movement from the crack so that side of the road remains open for now.
"Some geothermal bores in the area have been shut down to see if it has an effect on what's happening here, in which case it could be bore-related. We have well drillers here now looking to quench one of the bores to see if that affects the flow of water coming out of the fumarole," he said.
The council has called in sucker trucks to remove the mud to prevent it from getting into the nearby stream and a cesspit drain in the area has been blocked off.
Rotorua Lakes Council urged residents to avoid the area until the fumarole is fixed.
"Please avoid driving through Lake Road right now if you can and find alternate routes," the council said in a statement on its website.
The council said it is likely the steam was caused by high groundwater from recent weather.
Traffic management is in place and one lane is closed on Lake Road while the area is assessed, the council said.
