Radio New Zealand has just reported that two people have been arrested over the Supercity voting scam. Information removed to avoid possibly breaching a suppression order.
The initial charge is forgery, which carries a penalty of ten years jail. Other charges will apparently follow. The investigation is still continuing, so there may be other co-conspirators yet to be arrested.
As for what happens next, I expect there will be an electoral petition to ensure that the fraud has had no effect on the outcome. That could lead to the poll being declared void and a revote held.
Update: One sentence which may have identified one of the accused has been deleted to avoid any chance of breaching name suppression.