Forsyth Barr aviation analyst Rob Mercer says a price war on the Queenstown to Wellington air route will be difficult to maintain.
Mr Mercer says Jetstar's decision to take on the Air New Zealand monopoly between the two cities may be good for travellers, but will be hard for the airlines to maintain.
Air New Zealand has matched the $79 fares offered by Jetstar, which has launched even lower fare at $39 for a limited time.
Mr Mercer says Pacific Blue walked away from domestic routes in New Zealand last year after heavy losses.
Jetstar chief executive David Hall says he's confident his airline's strategy will endure.
He says the new flights will increase capacity into Queenstown by 11,000 seats per week.