Lines companies estimate about 13,300 properties are still without power in Canterbury, with some people likely to be without power for another four days, following Tuesday night's violent storm.
Federated Farmers adverse events spokesperson Katie Milne estimates the storm has cost farmers tens of millions of dollars in damage.
Many dairy farmers are using diesel generators to run milking sheds while others are taking cows to neighbour's sheds or stopping milking altogether. But Ms Milne says an even bigger problem is getting water to stock, with power cut to water pumps.
Federated Farmers North Canterbury field officer Pam Boland says communication is also a problem with phone lines down and cellphone coverage limited on many farms.
She says without the internet and cell network, it is almost impossible to communicate up-to-date information from lines companies to isolated rural properties.
On Thursday 9,000 Orion customers remained blacked out in mid Canterbury, mostly in the Selwyn district.
The lines company says because of the extent of the damage to power lines it's possible some will be without power for another four days.
Another South Island distributor, MainPower, says 4,300 of its customers in North Canterbury still don't have electricity. About 30,000 customers were cut off in the South Island at the height of the storm.
North Island lines company Powerco says it has restored electricity to nearly all of its lower North Island customers, with just 300 now without power. A total 10,000 of its customers in Taranaki, Wairarapa, Tararua and Manawatu were blacked out earlier.
An irrigation body says more than 800 irrigators across Canterbury appear to be severely damaged and will need to be repaired or written off.
Irrigation New Zealand says the situation is extremely serious because of a lack of parts to repair them.
Chief executive Andrew Curtis estimates there will be a six to eight week lag before parts arrive from overseas and then a similar timeframe before repairs can be completed.
Waimate District Council chief executive Tony Alden says his region is facing a massive cleanup after it was hit by winds exceeding 200 kilometres an hour. He says pine plantations and other forestry blocks have been destroyed.
Mr Alden says he does not know yet how much the cleanup will cost.
Selwyn District Council is offering hot showers and water to residents without power as well as water to farmers for stock.
The council is asking people to conserve water and avoid flushing toilets while it fixes damage to water supply schemes and sewerage systems. It says the lack of electricity to power water pumps is a problem.
Flights return to normal
Air New Zealand has been clearing the backlog of passengers stranded after the storm caused flight cancellations.
Wellington Airport was closed to domestic flights on Wednesday night because of high winds and further flights were cancelled on Thursday because Air New Zealand had been unable to reposition its aircraft.
The airline said on Thursday morning it had a backlog of 2,500 passengers from 23 cancelled flights. Jetstar was not expecting any problems.