Delays caused by unsettled weather have upset Ospri plans for an aerial drop of 1080 poison on land near Luggate this winter.
Corporate communications manager Oliver Bates said on Wednesday the operation targeting possums on 2000ha in the Alice Burn East area had been suspended.
"Farm managers need to shift ewes back into the area for lambing in September, leaving insufficient time for the rainfall required to reduce bait toxicity to safe levels for stock," Mr Bates said.
Ospri Southern South Island acting programme manager Jennifer Lawn said the organisation would work with landowners, contractors and its own disease management team "to decide when and how we control the possums in this area".
"Ground-based possum control on the land surrounding the Alice Burn East operation will continue for the next two years as planned while Ospri considers the next steps in responding to the Tb infection," she said.
The TBfree programme aims to eradicate bovine tuberculosis from New Zealand by 2055.
Possums are the main cause of bovine Tb in cattle and deer, and the Alice Burn operation was planned as a response to a locally-infected herd.
