Motorists are being urged to take care due to extensive flooding across Palmerston North.
Severe thunderstorms have struck near Palmerston North and Manawatu and are bringing very heavy rain and large hail.
A Metservice Severe Thunderstorm Warning for the region states these thunderstorms are moving towards the north northeast, and are expected to lie near Fielding, the Manawatu Gorge and Ashhurst at 5.30pm and spread to Pohangina.
Some roads have become completely impassable, including Roberts Line, James Line, Fernlea Ave and Branigan Parade.
Police are asking motorists to avoid these areas and take alternative routes.
Thunderstorm warnings are also in place for Waikato, Hamilton, Waipa and Otorohanga.
The storm is moving southsoutheast over the Waikato, and expected to lie near Cambridge, Te wamutu, Kihikihi, Ohaupo, Waikeria, Leamington, Tokanui, Rotoorangi, Maungatautari, Waikeria, Maihiihi, Paewhenua and Panetapu between 6.15 and 6.45pm.
NZ Transport Agency earlier reported there had been flooding on State Highway 2 at Norsewood.
A 30km/h speed limit and Stop/Go traffic management was put in place, but has now been lifted after contractors managed clean-up from earlier slips and flooding.
The Ministry of Civil Defence and Emergency Management advises that as storms approach you should: take shelter, preferably indoors away from windows; avoid sheltering under trees, if outside; move cars under cover or away from trees; and secure any loose objects around your property.
You should also; check that drains and gutters are clear and be ready to slow down or stop, if driving.
During and after the storm, you should also: beware of fallen trees and power lines and avoid streams and drains as you may be swept away in flash flooding.