New satellite images show more than 200ha of native habitat was converted to low producing grassland over a six-year period in Hawke's Bay.
About 40ha of indigenous forest and 170ha of tussock was converted in the region between 2012 and 2018, according to Manaaki Whenua Landcare Research data.
Forest & Bird, which released a series of before and after satellite images of land along the Napier-Taihape Rd at Ngamatea on Monday, claimed 12 of 13 native habitat types have seen an overall decrease across the country.
Forest & Bird regional manager Tom Kay said the Hawke's Bay environment has "reached breaking point".
"The area of indigenous habitat in the region is already extremely limited and the data shows it's still decreasing," he said.
"There has been a real drive in Hawke's Bay to do more for native species through the regional Biodiversity Strategy, but without some rules to support it we'll continue to see native habitat in Hawke's Bay shrink and watch our species slide towards extinction."
Kay added: "We need to protect these habitats like we protect our native species – with strong rules to limit further loss alongside a framework and resource to restore them."
Hawke's Bay contributed to an overall national loss of 1471ha of tussock and 2304ha of indigenous forest over the six-year period.
Forest & Bird chief executive Kevin Hague said the images show the level of biodiversity across the nation.
"Most of New Zealand is in private ownership, and many native species live on privately owned land," he said.
"Without clear guidelines for identifying and protecting important native habitat, our environment has been pushed to breaking point."
While Hawke's Bay suffered a total of 210ha of converted native habitat, in the West Coast, more indigenous native forest (1343ha) was cleared than in any other region, and converted into 383ha into mines and dumps, and 590ha into grass.
Canterbury landowners wiped out 1457ha of the shrub matagouri, more than any other region, turning it into pasture, while Manawatu-Wanganui converted 3544ha into pasture and exotic forest.
Hague added: "It is time to put nature first, and put in place a national policy to identify and protect the significant natural areas the country has left.
"Our native animals don't know if their home is in a national park, a farm, or someone's backyard. We need to lift the bar and get a clear, fair, and transparent National Policy Statement applying across the country that protects important habitat, wherever it is."
Hawke's Bay Regional Council was contacted for comment but was unable to respond before deadline on Monday.