Fonterra says its Maungaturoto milk processing plant in Northland is now operating again and it hopes to collect all milk from that region on Friday.
The Maui gas pipeline closure earlier this week stopped processing at 15 Fonterra plants in Northland, Bay of Plenty and Waikato, which use gas for heating.
Fonterra says the Te Rapa site in Waikato is now operating at half-capacity, but its Morrinsville site in Waikato and Tip Top factory in Auckland remain shut.
A spokesperson says Fonterra says hopes to collect as much milk as possible in Waikato and Bay of Plenty on Friday, but won't be able to collect all of it.
It says if milk has not been collected by 5pm, farmers on day pick-up must dump it. Those on night pick-up have until 5am on Saturday.
Fonterra estimates that so far farmers have disposed of 50 million litres of milk into effluent ponds and on to pastures through irrigation systems.