NZ PM Jacinda Ardern surveys flood-hit areas

New Zealand's Prime Minister Jacinda Ardern assessed the damage to farms and a major bridge in the Canterbury region as floodwaters receded on Tuesday.

Ardern told reporters the top priority was getting transport links working again, although it was unclear how long it would take to fix the bridge that connects the town of Ashburton to the main highway south.

Crews hoped to have an alternate route to the town ready by the end of the day.

Ardern said farmers had been particularly hard hit with lost feed, broken fences and debris spread across their fields.

She said seeing the damage from the air had shown her the scale of what had happened.

Still, there was some relief that the flooding didn't cause major damage to homes or result in more casualties.

A truck driver was killed Monday when a tree fell on the truck, although it wasn't immediately clear if flooding or rain was a factor.

As much as 40 centimetres (16 inches) of rain fell over three days in the Canterbury region, prompting authorities to declare a state of emergency and the government to allocate 500,000 New Zealand dollars ($364,000) toward cleanup efforts.

Several hundred people were told to leave their homes and schools were closed during the flooding.