The rules around the way you can pay and when you pay IRD, are about to change from 1 October this year.
Firstly you will not be able to make cheque payments to the IRD across the counter at a Westpac Bank branch. However you will still be able to make payments by cash or EFT-Pos.
Secondly, and more importantly, as from 1 October, payments made to the IRD must be received by the due date. This is a significant shift in policy and can result in exposure to interest and penalties if not followed. Therefore it is important that any payments by cheque must be posted well before the due date in order for the unreliable NZ Post delivery to get the payment (and return) to the IRD by the due date. Essentially the IRD are recommending (and wanting) us to move to electronic payments which will allow payments to be set and paid on the due date.
Watch your mailboxes as the IRD are promising to have lots of promotion about the changes.