Domestic customers who use the new pre-pay service will pay $30 for one extra bag and $50 for a second extra bag - half as much as the new excess fees.
Air NZ spokeswoman Marie Hosking said the higher excess fees would encourage customers to plan ahead and pre-purchase their baggage.
She said the charges reflected the cost of carrying additional weight on the aircraft, and the baggage fees did not constitute a large proportion of the company's revenue stream. Excess and overweight fees will also increase on international flights, with the cost of an extra bag to Australia to increase from $75 to $120 - more than double the $55 pre-pay cost.
The cost of an extra bag on other international flights will increase from $115 to $200, with pre-paid baggage to cost between $95 to $155, depending on the destination.
Customers will be able to book pre-paid baggage from this Thursday.
Air NZ customers will also be able to book preferred seats, for a cost, allowing them to choose seats with good locations, extra leg room or more personal space.
Ms Hosking said 70 per cent of customers could already select their seats for free, and the new service would allow the rest to pay to select a seat in advance.