Police have warned people to keep out of a Canterbury river as a massive volume of water is coming from the Southern Alps after a heavy rain event on Friday.

A statement from police this evening, said: “A large volume of water is moving down the Waimakariri River, carrying logs and debris following the rainfall on the West Coast.

“Anyone swimming or four-wheel driving in the riverbed area is advised to leave.”

The warning covered the area between the Waimakariri Gorge and the sea. The gorge is north of Springfield and the braided Waimakariri River reaches outfall just north of Christchurch.

Police said that, as of 6pm this evening, the large volume of water was moving bank-to-bank through the gorge and could pose a threat to anyone in the flow area.

There is no current risk considered to anyone outside of the riverbed area.

Coincidentally, up to 40 firefighters have been working to contain a “deep seated” vegetation fire in a stretch of the Waimakariri River bed this afternoon.

The fire was reported at 2.50pm on Saturday on the north side of the riverbed in Swannanoa, northwest of Christchurch.

Fire crews were expected to continue working overnight and into tomorrow, with estimates that the fire is burning an area roughly 12 hectares.