Foreign Minister Winston Peters is not practicing what he used to preach.

Political editor Barry Soper says Mr Peters' description of National leader Don Brash as evil for defining Maori on the amount of blood coursing through their veins is an argument he has used in the past.

Mr Peters said Dr Brash's alleged attempt to link being Maori to a quantum of blood was not only ignorant, but also reveals a venal attempt to assimilate all that is good about Maori culture and heritage.

However in a speech six years ago, Mr Peters, who coined the phrase sickly white liberals, called for an end to a dual electoral system in which the only qualification to vote is based on race, in some cases as diluted he said, as one part in five hundred and twelve.