As Auckland tries to house its bulging population, the city is being warned that losing prime agricultural land may mean it struggles to feed its people.
An internal Auckland Council report has found that nearly 10 percent (8.3%) of the best quality land has been converted from food-producing land to urban developments in recent times.
That equates to 10,399 hectares, or the equivalent of 15,000 rugby fields, and the majority of that - 10,080 hectares - changed hands between 1975 and 2012.
The report says the transformation has accelerated since 1996 and since then most urban expansion has occurred on high class agricultural land. The bigger problem though is that this top quality soil makes up only 1 percent of Auckland's soils.
And the conversion is expected to get worse as the region tries to jam in an extra million people by 2040. With a forecast of 2.5 million people by then, the council says there will be immense pressure on the region's soil resources.
It says there is a need to analyse the economic benefits and long term sustainability of future development against the protection of top agricultural land for current and future production requirements.
Case study - Pukekohe
Pukekohe is considered one of the food baskets of the country, providing fruits and vegetables to supermarkets up and down the country.
Its proximity to major centres, access to rail and ports, and its frost-free weather has led to that status.
But Pukekohe is in the process of having a large amount of its land re-zoned for housing.
That means there is a strong chance that the city will need to import food from other regions, and will inevitably mean food price increases for Aucklanders.
Special Housing Areas - how do they work?
The Auckland Council has teamed up with the Government to free up more land for housing and recommends places where that can occur and the Government signs it off.
The benefit being that houses in those areas have proactive council pre-application processes, fast-tracked consenting and limited notification and appeals.
The Auckland Council is also re-drawing the rural-urban boundary to allow room for more urban development.
That will see housing spread outwards, rather than having more multi-story attached housing.
Pukekohe will be part of three Special Housing Areas and the boundary change will also affect some housing.
The Council intends on making it a satellite town to accommodate 50,000 dwellings - the majority on the highest quality land in the region.
The boundary changes will form part of Auckland's over-arching Unitary Plan which will next month go into the hearing phase.
An independent board looks at the council's plans, hears submissions, and can recommend changes be made to the council.
A grower's story
David Clark's family has been growing celery in Pukekohe for the past 50 years.
They produce 50 acres of celery each year, supplying to Foodstuffs supermarkets.
But their nursery in Pukekohe has been earmarked as a Special Housing Area meaning his land will now be considered urban rather than rural.
He says he is in limbo, because whilst no-one has offered to buy his property or business, he fears he will be driven out of the area once it becomes over-run with city-siders.
He says neighbours already complain about noise, irrigation and spraying and it will be harder to get consent once he has more neighbours to battle with.
Mr Clark is challenging the re-zoning of his land, and will make a submission at the Unitary Plan meeting.