Motorists have been urged to avoid travelling along rural highways in Manawatu and Whanganui unless it is essential, as heavy rain continues to cause widespread slips, surface flooding and closures.
The New Zealand Transport Agency said all highways had been affected by slips, debris and surface flooding in the Manawatu and Whanganui areas.
SH4 between Whanganui and Raetihi was now closed due to multiple slips and trees blocking the road.
SH3 between Bulls and Whanganui was closed due to flooding.
SH1 between Bulls and Hunterville was also closed, and SH54 was closed, meaning there was no detour available. The only north-south route open between Wellington and Hawkes Bay was now SH2.
SH3 through the Manawatu Gorge was open, although there had been a number of minor slips.
Meanwhile, SH1 north of Manakau in Horowhenua remained closed, due to floodwaters undermining the banks of Waikawa Stream Bridge.
The highway was likely to remain closed until tomorrow at the earliest as crews worked to restore the bridge, the Transport Agency said.
Central regional performance manager Mark Owen said motorists travelling between Manawatu and Kapiti or Wellington, would need to use SH2 and SH3 as a diversion.
As this was a significantly longer route, motorists would need to allow extra time for their journeys.
"We recognise that the diversion is a major inconvenience for travellers and the freight industry, and our contractors are working hard to get it safely reopened," says Regional Performance Manager Mark Owen.
"There's been a huge amount of rain, and it has caused the river to rise and wash away parts of the bank that the bridge relies on for support.
"Safety is our first priority, and we need to make sure the bridge is safe and secure before it reopens to traffic."
He said contractors were working throughout the highway network to clear roads and respond to hazards.
"We have crews out in force throughout the network dedicated to getting the roads cleared and safely reopened as soon as possible."
The New Zealand Transport Agency said the Manawatu Gorge was now also closed due to slips.
Due to the large number of road closures police urged motorists to check the Transport Agency's website for roading updates.
Police were continuing to advise anyone in the Manawatu or Horowhenua area to avoid travelling on the roads unless it was absolutely necessary
*SH1 near Marton just south of Calico line
*SH3 between Bulls and Wanganui
*SH3 Hawera to Patea
*SH4 between Raetihi and Wanganui
*SH53 The Waihenga Bridge
*SH3 Manawatu Gorge
*Saddle Road still open but with numerous slips with significant delays
*SH43 Startford to Taumaranui
*SH54 Vinegar Hill to Cheltenham
*SH56 Closed at Opiki