Mr Munro said Mr Tau was previously hapu kaikorero for Ngati Hinemutu, a smaller hapu, but resigned so he could be nominated for the Ngai Tawake position.
But Rudy Taylor, co-chairman of Te Kotahitanga o Nga Hapu Ngapuhi, the group which opposes Tuhoronuku, said it was not right for Mr Tau to accept the nomination, particularly after calls for him to consider quitting other positions.
"Sonny is confused, he doesn't know when to be embarrassed. He should have stepped down and said 'I'm declining these roles'. Ngapuhi needs a leader and a good role model, not someone who has [allegedly] broken the law," Mr Taylor said.
The hapu kaikorero is to be the communications line between hapu, negotiators and Tuhoronuku. An election will be required to elect one for Ngai Tawake. The other nominee is Adrianne Junellie Taungapeau.