The west branch of the Matukituki River. Both branches of the river have been declared off limits over the next few weeks. Photo: Pseudopanex/Wikimedia Commons

Hunters, hikers and anglers are being warned not to enter the east and west branches of the Matukituki Valley for the next few days during a Department of Conservation aerial 1080 operation, which starts today.

Doc Central Otago district senior ranger Annette Grieve said a helicopter would be flying over the east and west branches of the Matukituki Valley and distributing the toxic pellets according to predetermined flight paths controlled by GPS.

She said the cylindrical cereal pellets were cinnamon lured and dyed green to deter birds but were poisonous to humans and domestic animals.

Poisoning could occur by eating baits or poisoned animals, including carcasses, and fishermen should wait up to seven days before consuming trout.

``All tracks in the east and west branch of the Matukituki Valley will be temporarily restricted while the helicopters are operating and for up to 24 hours during the toxic drop.''

``Immediately after the drop the tracks will be inspected by Doc staff and cleared of pellets but it is strongly recommended that people do not enter the treatment area until the tracks are cleared,'' she said.

As part of the 2017 ``Battle for our Birds'' predator control, Doc identified the Matukituki Valley as a priority area where native populations were under threat from predation by stoats and rats, Ms Grieve said.