In a post on its Facebook page today, Orokonui staff said initial indications from autopsies of the birds suggested "the ingestion of an anticoagulant toxin was the cause".
The wildlife reserve is in the Orokonui Valley between Waitati and Purakaunui, 20km north of Dunedin city.
Orokonui staff have contacted Ospri, which is managing a large TB control programme in the Dunedin area.
This resulted in a rapid response from Ospri, and its contractors removed bait from stations across the entire operation area of the programme as a cautionary step.
Both kaka showed similar symptoms before they died: unusual swaying behaviour, looking lethargic and ill.
Orokonui wants residents in communities surrounding the ecosanctuary to keep an eye out for any kaka - well or otherwise - and to immediately report sightings.
Contact the Department of Conservation's hotline on (03) 477-0677 from 8.30am to 5pm weekdays, or after hours on 0800 362-468.
Dunedin’s Wildlife Hospital is on standby to treat any sick birds.