Five crews of firefighters are working to control a fire in the Waimakariri riverbed near Kirwee this morning.

The blaze, which was reported late last night, has burned through about 8 hectares of scrub. Ground crews are being supported by two helicopters, while a digger and an excavator are being used to create a firebreak to stop the flames from advancing towards nearby forestry.

No structures are currently at risk, but authorities have asked the public to stay well away from the area today.

Fire crews remain on-site as they work to bring the situation under control.