Auckland-Brisbane flights will move from up to 10 a week to twice daily, with 99,000 more seats a year.
Auckland-Sydney flights will also be more frequent, from eight per week to 12 a week. Jetstar said 79,000 seats will be added to this service.
Jetstar will fly from Christchurch to Melbourne every day all year long, with 26,000 additional seats on that route.
And the Auckland-Dunedin service will increase from seven flights a week to 10 a week from October 26 to May 17, with 24,000 additional seats a year.
Jetstar will base another Airbus A320 in Auckland.
The airline said it had also re-timed its Auckland-Wellington flights to a 7.30am departure.
It said that would give business and Government travellers more convenience and choice.
Jetstar said the expansion would also cater for New Zealanders travelling to Asia using Australia as a springboard.
“Double daily services from Auckland to Brisbane will allow customers to connect to Osaka, Tokyo, Seoul, Bangkok, Phuket and Cebu, with one short stop in Brisbane.”
It said more Christchurch-Melbourne flights would allow Kiwis to head from Melbourne to Singapore, Bangkok, Bali, Phuket and Ho Chi Minh City.
“The carrier has also brought forward departure of its Christchurch to Cairns flights to 7am to allow for connections via North Queensland on to Tokyo.”
Jetstar group chief executive Stephanie Tully said the expansion would boost Jetstar’s New Zealand domestic capacity by 18% and by 14% across the Tasman.
“These changes will give a much-needed boost to inbound tourism while offering Kiwis even more low fares and choice in how they travel,” Tully said.
The airline’s announcement comes as New Zealand has for many months struggled to reach pre-Covid inbound tourism numbers.
Stats NZ today said overseas visitor arrivals were 236,600 in July 2025, an increase of 14,700 from a year earlier.
The total number of overseas visitor arrivals in July was 93% of the July 2019 numbers, before the pandemic.
Jetstar announced the new routes at 3pm today and said it would have a network-wide sale.
One-way sale fares included Christchurch to Wellington from $42 and Auckland to Osaka via Brisbane from $432.
Meanwhile, Qantas said it would start flying its Airbus A220 on the Wellington-Brisbane route.
Airbus said the A220’s overhead bins had the largest stowage capacity in their class.
Qantas said the narrow-body twin jets had almost double the range of their Boeing 717 predecessors.
The Airbus A220, A320 and A350 aircraft Qantas has on order.
The airline said the A220 had 25% fewer CO2 emissions than the older-generation aircraft.
The new aircraft joined the Qantas fleet last year.
Qantas said the aircraft had big windows as well as fast and free Wi-Fi.
The A220 also had integrated personal device holders and USB chargers in economy and business classes, plus wireless charging pads in business class.
The Qantas and Jetstar announcements also followed some high-profile struggles for regional airlines.
And airlines generally have been complaining this year about rising fees imposed by airports, air traffic control and aviation security.
“We’re working closely with the New Zealand Government to manage rising costs in the market,” Tully said.
She said Qantas and Jetstar were grateful for the Government’s “commitment to ensuring sustainable growth for air travel to and within New Zealand”.
John Weekes is a business journalist covering aviation and courts. He has previously covered consumer affairs, crime, politics and courts.