Auckland-bound motorists can use State Highway 2. Waikato-bound motorists can use SH36 via Ngongotaha and SH5.
UPDATE 4.54pm: SH29 has been closed in both directions while the serious crash unit is in attendance, after one person died in a crash and another was injured.
Police have asked motorists to avoid the area.
4.05pm: Police have confirmed one person has died in a crash on SH29 on the Lower Kaimai Range, and another has been injured.
The person's injuries are unclear at this stage.
Traffic can still get through the partially closed road, but there would be "significant" delays.
3.51pm: There has been a serious crash on the Lower Kaimai Ranges, on SH29 near McLaren Falls Rd.
Police have confirmed a person has died in the crash.
A reporter at the scene saw a person on a stretcher being placed into an ambulance.
A police spokesperson said emergency services were called at 3.30pm to a two-car accident.