The low cost airline says it will also start three times a week Wellington-Dunedin services from late October.
Jetstar head of New Zealand, Grant Kerr, said customers had regularly requested the airline add a Wellington-Dunedin service to bring more competition to the route.
Wellington Airport said the new service will add 56,000 seats to Wellington's domestic market and provide onward connections to Australia.
Kerr said more than 5000 extra seats would also be added over summer between Christchurch and Melbourne.
The airline was also making progress with plans to use QantasLink Q300 turbo-prop aircraft to serve the regions.
"We've now visited all the regions under consideration and we've had a very positive response from everyone we've spoken to about our new services," Kerr said.
The airline used the 787 on the Auckland-Melbourne route for a month at the beginning of last year.