Pea weevil larvae feed on young peas, ruining crops and potentially threatening valuable fresh and seed pea exports.
The official declaration ends a nearly four-year ban on growing peas and use of pea-straw in Wairarapa.
The pest was first discovered in the region in 2016. Two complete seasons of no new finds was required to ensure the pest had been eradicated.
Biosecurity Minister Damien O'Connor said the successful eradication of the noxious pest from Wairarapa was thought to be a world first.
"To our knowledge, this is the first time a pea weevil population has been successfully eradicated anywhere in the world. This just goes to show what can be achieved when government, industry and communities work together.
There was good cooperation between farmers and gardeners in Wairarapa and Biosecurity New Zealand, O'Connor said.
"It was a great effort.
"Farmers had to give up the opportunity for significant valuable cash crops ... but there were ex gratia payments from government to compensate them for that."
"At a time when the world is focusing on alternative proteins, on plant proteins, to work alongside animal protein, then things like peas are really important for us and for farmers to be able to grow them".
Wairarapa farmers will be able to get back to growing peas in next season and supplying seed peas to Canterbury. All commercial seeds grown within a 5km radius of Masterton will be checked next year, O'Connor said.
Overseas, pea weevils are found in many regions, including the United Kingdom, Australia, and North America.
Federated Farmers arable chair, and Wairarapa grower, Karen Williams said the decision to eradicate was hard on local pea growers so it was extremely pleasing to see their efforts rewarded.
"The pea industry is worth $130 million to New Zealand. Wairarapa growers and farmers were initially aghast at talk of a ban on growing, for years,
"There were some dark days early on, and a few testy conversations. But I'm proud of the way the farming community and the public responded to this crisis," she said.
Williams said the next step for industry is to work with seed companies to bring back pea growing contracts.