A number of South Island state highways are closed due to heavy overnight rain. In the North Island, dozens of flights at Auckland Airport have been cancelled due to fog.
Drivers across the South Island are urged to take caution as a number of roads are affected from heavy overnight rain.
The Haast Pass is closed due to flooding, and there is surface flooding across a number of state highways this morning.
Area warnings are in place for State Highway 8 between Twizel and Farlie and between Ōhau and Mount Cook, and State Highway 6 from Hokitika to Fox Glacier.
A MetService orange rain warning is in place for the Main Divide and the West Coast until after midday.
Canterbury Regional Council is warning farmland could be flooded as foothill and alpine rivers rise today.
It said erosion from recent floods had weakened some river areas, and high flows today would likely cause further damage.
The Ashburton River may overflow, though the Opihi is expected to stay within capacity.
Council said it would be monitoring vulnerable areas.
Meanwhile, Christchurch motorists have been told the westbound lanes of Harper Ave, at the northern end of Hagley Park, are blocked due to a fallen tree.
Contractors have been advised but police said the tree is likely to take "some time" to remove.
Fog restrictions at Auckland Airport have been lifted.
For the third morning in a row, dozens of flights were cancelled or delayed because of fog.
About 28 domestic flights were delayed and 43 were cancelled due to the weather conditions.
International flights were not affected.
The disruptions to outgoing and incoming flights involved several airlines flying to or from regions including Palmerston North, Whakatāne, New Plymouth and Blenheim.
Air New Zealand said the cancellations involved turboprop planes on the regional network.
It said passengers would be put onto alternative services throughout the day to clear the backlog.