The ACT Party leader, Don Brash, has been accused of using desperate tactics to bolster the party's support.
ACT ran an advertisement in Saturday's New Zealand Herald featuring the Maori sovereignty flag, and asking people whether they are "Fed Up With Pandering To Maori Radicals?".
Dr Ranginui Walker, an Emeritus Professor at Auckland University, says Dr Brash is using the same tactics he did in a speech at Orewa in 2004, when he attracted attention for his views on supposed Maori privilege.
But he says any visit to a marae will quickly reveal that far from being privileged, Maori are among the country's poorest people.
He says the advert is a sign of desperation, but its message will only appeal to a narrow band of voters with racist attitudes.
In a statement, the Maori Party says the advert is deeply offensive, but it won't comment further.
The National Party has also declined to comment.
Brash brands newspaper cowardly
Dr Brash has branded a daily newspaper cowardly for not accepting the advertisement.
The half-page ad ran in the New Zealand Herald on Saturday.
It urges people to give their party vote to ACT so it can, as the party puts it, stop National trading away the country's resources for Maori Party votes.
Dr Brash says the Herald published the ad without hesitation, but the other paper to be offered it, The Dominion Post refused, in part, he says, because it considered the headline to be offensive.
He says that's an extraordinary and cowardly decision.
Dr Brash says the ad restates the party's One Law for All campaign in the face of moves by successive governments to entrench privileges for Maori.
He says this includes unelected Maori boards at local government level, the proposed control by Maori over flora and fauna put forward in the Wai 262 claim, as well as National's failure to abolish the Maori seats as it promised.
"It reflects a very deep frustration on the part of many people that successive governments, Labour and National, have been trying to appease a group of quite radical Maori, who have a view of New Zealand that is not only fundamentally different from what most New Zealanders want, but fundamentally different from any reasonable interpretation of the Treaty of Waitangi."