United Future has called on the National Party to drop its "totally divisive" policy of simply getting rid of the Maori seats in Parliament.
The policy has already caused the Maori Party to vow it will work to stop National gaining power, and United Future's statement could create problems inany coalition talks after the election.
United Future leader Peter Dunne said his party had "very serious concerns" about the damage that a unilateral decision to abolish the seats would have on New Zealand's social fabric.
"Their policy is a blunt tool and it's a recipe for serious racial disharmony at a time when we, as a nation, need to be building bridges rather than burning them," he said.
"United Future does believe the Maori seats should go - but we don't support a crash-through-or-burn approach to an important and sensitive constitutional issue."
Mr Dunne said substantial consultation should take place before any decision was made.
"And frankly, this is the kind of issue that should go to a referendum," he said.
"In the end, a bunch of largely white MPs should not get rid of Maori seats.
"I think as a nation we would regret such a decision being made in that way."
