The Greens are demanding the end of perpetual leases on Māori land, labelling them an outdated and unjust colonial weapon.
Some 26,000 hectares of Māori land are leased out under conditions set by the Crown with a right to renew forever.
Speaking at Waitangi, Green MP Elizabeth Kerekere said it meant many Māori landowners have been locked out of their own whenua for generations.
"One hundred and twenty years ago, land reserved for Māori was leased to European settlers at the expense and considerable disadvantage of those Māori land owners," she said.
"So the government took control of the land, they decided who to lease it to, they leased out for next to nothing, and gave them the right to renew those leases forever, or without the consent of those Māori landowners."
That had resulted in a decades' long injustice, deprivation and poverty for affected whānau, hapū and iwi, Kerekere said.
"Those lands continue to be perpetually leased out," she said.
"And those landowners continue to have no say in that, but they're the ones paying the price.
"So much so, that if they want to regain control of their land, they have to pay the full market rate to buy their own land back.
"Our people have suffered for 120 years too long. This is an injustice that can be simply ended by law."
The remote settlement of Tokomaru Bay is one example where land is leased out to a number of groups, but provides next to no income for its beneficiaries, as it is subject to the legislation which severely limits the owners' options.
Kerekere wants a law change, and new arrangements settled.
"Our priority is to end the perpetual leases, then the process can start because ... those Māori landowners may well decide to keep leases with those same people, but they renegotiate it on their own terms."