Acting Waikato Transport System manager Rob Campbell said the slip repair works were being undertaken on a narrow section of road and there was not enough space to allow traffic past while work was underway.
"Our contractors are also taking advantage of the road closure to deliver other essential road maintenance tasks."
Motorists are encouraged to plan ahead for travelling as the detours for this route "are significant," Campbell said.
Southbound detour:
Travel south on State Highway 2 from Waihi to Tauranga, then onto State Highway 29 over the Kaimai Range, State Highway 24 to Matamata, State Highway 27 to Tatuanui and State Highway 26 to Paeroa.
Motorists travelling from Paeroa take the same route, in the opposite direction.
Northbound detour:
Those travelling from Waihi should take State Highway 25, turn onto State Highway 25A (Kopu-Hikuai Rd) and then State Highway 26 between Kopu and Paeroa.
Motorists travelling from Paeroa take the same route, in the opposite direction.