More than 40,000 hunters are expected to be out this morning for the opening of the duck season.
Fish & Game New Zealand said the breeding season had gone so well that in some regions the bag limits had been raised.
Spokesman Don Rood said decisions on limits were made after close monitoring of the bird population.
Mr Rood said it was up to individual hunters to know the limit set in their own region.
Duck shooters were advised to respect the bag limits and to have an up-to-date game bird licence.
Mr Rood said Fish & Game officers would be out enforcing the rules.
"My message to hunters is that when a ranger approaches a maimai they co-operate and the shorter time they spend there, the more time hunting shooters will get."
Mr Rood said police would accompany some rangers and would be checking on firearms licences.
Fish and Game said duck shooters needed to take particular care and not mix hunting and alcohol.
Last year, a 21-year-old hunter died after his gun went off while he was climbing over a fence, and a 15-year-old boy died while shooting in the eastern Bay of Plenty.
Mr Rood said the simple message to hunters was to be very careful.
"Drink and firearms do not go together any better than drink and driving goes together."
He said a drink after the event was fine and is part of the normal social activity New Zealand accepted.
"But not in the maimai, not while hunting and not while handling firearms."
Fish and Game regions which have relaxed their regulations on bag limits because of better bird populations include the Eastern region (including Rotorua and Taupo lakes, Tauranga and East Cape), Wellington, Nelson/Marlborough and Southland.