The Hawke's Bay A&P Society is considering an approach made to it to develop the majority of the Showgrounds Hawke's Bay Tomoana into residential housing.
The proposal has already sparked vociferous opposition from some of the region's leading agricultural figures.
The 40-hectare showgrounds were originally purchased from William Nelson in 1911 and have been home to the Hawke's Bay A&P Society ever since.
It hosts some of the region's and New Zealand's largest events, including the weekly Hawke's Bay Farmers' Market, the A&P Society Hawke's Bay Show and New Zealand's Horse of the Year event.
Apple grower John Bostock, a member of Save Our Fertile Soils Society, said he had been approached by the A&P Society and developers for his support of the "incredibly short-sighted" development.
"We will employ every resource possible to stop the vandalistic developers from ruining this beautiful, historical piece of land," Bostock said.
"This proposal has not been thought through, with no account of what this amazing piece of land means to the people of Hawke's Bay.
"We are committed to fighting this and we won't stand back and watch."
A & P Society general manager Sally Jackson confirmed an approach had been made about six weeks ago to the society regarding the showgrounds.
Jackson said approaches to develop the showgrounds were common and had in the past included the likes of a hotel, museums, a road bypass and even a council food hub.
"We are no strangers to approaches," Jackson said.
"The executive committee has spent roughly six weeks investigating this and is presenting it to the general committee.
"The whole purpose of that meeting is to inform the general committee and get their feedback."
Jackson said because it was "such early stages" she would not comment on the type of development or its scope, including if it would encroach on the Waikoko Gardens, home of the Hawke's Bay Farmers' Market.
"Nothing will happen without the approval and guidance of our general committee," Jackson said.
"It is beyond early in terms of seeking feedback."
Hastings District Council mayor Sandra Hazlehurst and executive Nigel Bickle said the council had been informed by the Hawke's Bay A&P Society that they had been talking to developers about opportunities at the Showgrounds, including housing.
"We thanked them for letting us know, and informed them that the showgrounds is not designated in the Heretaunga Plains Urban Development strategy for housing, that it is zoned plains production land," the pair said in a statement.
"Council has not received any applications for any development activity on showgrounds land."
Bostock said he was not against development and building houses but believed there were other places for urbanisation to take place on unproductive soils, without using the country's most productive land and much-needed urban green spaces.
"The Heretaunga Plains have driven our Hawke's Bay economy for hundreds of years and will continue to do so. That is why we need to work hard to protect these incredible soils."
Leading grower and fellow Save the Plains Campaigner Paul Paynter said it was "ludicrous" to see the land being considered for residential development.
"This is not only the most fertile land in the world, it's a piece of land which has so much history associated with it," Paynter said.
"Now they are moving to wipe the history books by selling out to greedy developers. To even be thinking about it and tabling such a proposal is very short-sighted."