A former Maori Party candidate for the Ikaroa Rawhiti seat, Derek Fox, says Parekura Horomia made the seat his own with his close attention to its constituents, but it remains a Labour seat.
Labour, the Greens, Mana Movement and the Maori Party are all contesting next month's by-election which was left vacant by the death of Mr Horomia.
Mr Fox told Morning Report that parties such as New Zealand First and National are not running and Maori have left the Maori roll so they can vote for their choice of candidate.
He said all that will cement support for Labour.
Earlier, Labour candidate Meka Whaitiri said that while she believes support for Labour has grown in Ikaroa Rawhiti, she is not taking the seat for granted.