A number of cows have been spotted stranded by landslides on the coast north of Kaikoura, following Monday's 7.5 magnitude earthquake.
The quake hit around midnight near Culverden, causing extensive damage to property, closing businesses and transport links and killing two people.
It could also be a season-ender for dairy farmers, who have already had to deal with drought conditions for years.
Federated Farmers' north Canterbury dairy spokesman Michael Woodward says milking sheds from the epicentre right up to Kaikoura have been damaged, with farmers unable to milk at all.
Those without power are choosing not to use back-up generators that run on water, because they need to conserve it for their stock.
Slips have also cut off tanker access to farms, meaning milk will be dumped because it can't be held in a vat for more than 24 hours.
Fonterra says disruption is expected to milk collection due to road closures at the top of the South Island.
It estimates around 30 farms in Kaikoura will not have their milk collected, and others around the country may have their collections delayed as tankers are rerouted.
"We're doing our best to reach everyone who is due for collection immediately," says Fonterra's farm source chief operating officer Miles Hurrell.
"With power out and phone lines down in some area, that includes putting Farm Source teams on the road to go door-to-door to try to update those farmers with the latest information."
Most of Fonterra's manufacturing sites are processing milk as usual today.
The quake could have a flow-on effect for next year, says Mr Woodward, as it's the middle of mating season.
Technicians need to travel between farms to artificially inseminate the cows and if they can't, it could jeopardise next season.
"Although it's not affecting the cows in a major way, it is decreasing the amount of milk produced per cow for the season," he says.
The earthquake also saw the New Zealand dollar decline in response, but ASB economists say the effect "appears fairly limited".
The bank says that on Monday morning the NZD was 1.5-2 percent lower against most crosses and down just 0.5 percent against the AUD.
Following the quakes, shares in Fletcher Building went up 2.7 percent, while Tower Insurance fell 8.2 percent.
If the economic fallout continues and confidence drops, ASB says it could increase the odds the Reserve Bank will cut rates next year.
The Reserve Bank's next scheduled official cash rate review is in February.
While initial indications are that there's been limited economic impact, the full implications are not yet known.
"Several provincial towns have been hit hard, but to date only moderate damage has been reported in New Zealand's major urban centres. However, it is too soon to say without further information on the extent of damage and disruption, particularly around infrastructure," says ASB.
It's likely South Island transport infrastructure and Wellington's CBD will bear the brunt of the short-term "economic disruption".
The bank is also predicting a boost in construction demand at a time where the industry is already stretched, and there's a risk tourists may stay away or postpone their trips.