All tracks in the Dart, Routeburn and Caples will be closed during the drop. Nearby tracks will also be shut including Fraser and Kay Creeks, the Rock and Beans Burn and the Routeburn North Branch.
These closures will be up to 24 hours.
Overnight trampers already within the area will be held at huts by Department of Conservation staff until operations are complete.
People planning to visit these areas are advised to check with a Doc visitor centre prior to their trip.
A press release from Doc states: "Immediately after the drop the tracks will be inspected by Doc staff and swept for pellets before being reopened. Please note some pellets may still be found on the tracks, particularly if it is windy.
"If we encounter difficult operating conditions the aerial work may continue into Saturday, September 21. If this occurs, both the road closures and track closures will continue for this extra day.''
The road to Chinamans Bluff (Dark Track) closes later today, from the forest edge at the top of Mill Flat, and will remain closed on Friday.
FACT BOX
- Do not touch or eat bait
- Watch children at all times
- Do not eat animals from this area
- Poison baits or carcasses are deadly to dogs