South Canterbury farmers and Transpower remain at an impasse over demands for rental payments in return for access rights to paddocks.
A group of 50 farmers had threatened to lock out line workers from Wednesday if the grid operator did not offer a compensation plan.
Spokesperson Tom Henderson says the ultimatum remains in place.
He says it will come into effect when Transpower gives the statutory 10-days' notice of its intention to enter a property.
Mr Henderson says workers will be barred if Transpower does not offer a compensation deal during that 10-day window.
Transpower has stayed off the land in recent months but needs to return to complete a pylon upgrade before winter.
