Helicopters are being used to help battle a fire in a stand of trees in South Otago this afternoon.

A Fire Service spokesman says the trees near Kaitangata are between 6m and 8m tall.

Crews from Kaitangata, Balclutha, and Clutha Valley had been fighting the fire in Wangaloa Rd since 1pm.

A fire service spokesperson says the size of the blaze was unknown.