Hall said his airline wanted to grow the pie rather than cannibalise the competition.
Jetstar had been flying across the Tasman for a decade and main trunk routes with jets for more than six years and those operations were profitable last year.
"We've got a very efficient operating model," he said.
"We're not going to be profitable overnight (in the regions) but we're a very rational competitor and this will be sustainable."
At full list prices the value of the five 50-seat Bombardier Q300s regional planes nine A320s was close to $500 million, representing a substantial investment for Qantas-owned Jetstar, said Hall.
The airline has been flying between Auckland, Napier and Nelson last December and today added flights from Auckland to New Plymouth and Palmerston North, and Nelson to Wellington.
This year Jetstar would have more than 600,000 on its regional network.
Hall said on time performance of regional services was improving.
"It's performing in line with expectations. When you've only got a small fleet small movements can have a big percentage impact."