Northland DHB came in second, having spent $913,900, despite still having the lowest vaccination rates in the country.
Hawke's Bay District Health Board was third.
Covid-19 spokeswoman for Te Whatu Ora Te Matau a Māui Hawke's Bay - formerly Hawke's Bay DHB - Allison Stevenson said the incentives were aimed at better protecting communities from Covid-19 by reaching pockets of the population yet to get their first or second dose.
It continued its incentive programmes even after the nationwide Super Saturday campaign in order to target harder to reach populations, she said.
"Vaccination incentives covered special clinics, music, food and gift cards for receiving vaccination and spot prizes. The incentive programme ran smoothly with uptake figures higher on incentive days."
Hawke's Bay achieved its 90 per cent double dosed national target on December 31, 2021.
"The vaccine rollout was not possible without a large dedicated workforce both in the clinical and non-clinical space working hard behind the scene and within vaccine clinics," Stevenson said.
"The DHB together with community health providers, iwi, councils and leaders all worked tirelessly to reach people, no matter where they lived to help our region to get across the 90 percent double dose finish line at that time."
The spending of other district health boards varied wildly, with some shelling out hundreds of thousands of dollars, some spending tens of thousands of dollars, right down to frugal DHBs down south which spent a mere $5000 or even zero dollars.
National Party health spokesman Shane Reti has questioned the overall effectiveness of the funds spent in Northland, which did not meet the 90 per cent double dose target.
Southern District Health Board was the most frugal of them all.
Interim district director Hamish Brown said the policy of the Health New Zealand Southern Covid-19 Vaccination Programme "has been to not offer the public incentives to be vaccinated".
"The programme's resources have been focused on the setting up of community clinics and outreach activity to eliminate access barriers to the vaccination.
"On occasion, the community clinics offered manaaki, after the vaccination, and this was often sponsored by the community."