Vehicles surrounded by floodwater under the rail overpass at Sawyers Bay. Photo: via Facebook

State Highway 88, from Dunedin to Port Chalmers, is closed near Sawyers Bay due to major flooding.

The road beneath the railway overpass at Sawyers Bay has been inundated with about half a metre of water.

A local resident said other parts of Sawyers Bay were also experiencing flooding, and it was "unusual".

Apart from the heavy rainfall across Dunedin, she said it was not known exactly what was causing it, but believed it could be a blocked drain.

People wanting to get to Port Chalmers were being urged to turn off at Sawyers Bay and take Borlasses Rd.

NZ Transport Agency has said the affected section of road will be closed until further notice.

Dunedin Mayor Sophie Barker said AI-generated fake photos of flooding had been circulating online, which had been "very unhelpful" for people working in the Civil Defence bunker.

"The challenge is that some people are posting fake AI stuff, which is completely and utterly unhelpful."

However, this one (shown above) was real, she said.