A slip has cut off the main road into the small Waikato settlement of Kawhia.
The seaside town is all but cut off after a slip spilled across State Highway 31 late last night halfway between Braine Rd and Raglan Rd.
Waikato Police say it is so large it is going to be a while before it's sorted out.
It is likely to affect school bus services for secondary students travelling to Otorohanga.
Kawhia is not completely isolated, with an alternative winding gravel road to travel on.
Motorists who travelled on SH31 hours before the slip happened posted on Facebook that the cliffs appeared to be on the verge of collapsing.