Qantas Airlines has reduced its order for the Boeing 787 Dreamliners for its Jetstar subsidiary to 14, as it prepares for slower growth on its long-haul routes.

Jetstar, which competes with Malaysia-based Air Asia X and Singapore Airlines-backed Scoot for low-cost, long-haul passengers, is still expected to pick up its first Dreamliner this year.

Qantas Chief Executive Alan Joyce said plans for Jetstar to continue growing has not changed.

"While the plan is for Jetstar's long-haul network to keep expanding, we are using the flexibility in our agreement with Boeing to cancel a firm order knowing that we can replace it with one of our 50 options for this aircraft down the track, and with a full view of what market conditions are like at the time," Joyce said in a statement.

With Qantas' 50 options to buy Boeing 787-8 and the larger 787-9 aircraft from 2016, the airline group could still put a 15th Dreamliner in the Jetstar fleet if it wished to and if conditions supported more growth at Jetstar.

The decision to reduce its 787 order was made late 2012, Qantas said, before the Dreamliner's grounding by regulators in the US on Thursday and an investigation into the aircraft's lithium ion battery.

Joyce said Qantas remained firmly committed to the Dreamliner and was confident current technical issues would be resolved by Boeing.

Meanwhile, Qantas said it was leasing a further five Boeing 717 aircraft and Bombardier Q400 turboprops, due to arrive in the second half of the year, to support more regional flying.

Qantas said the changes would have no impact on the company's planned capital expenditure, expected to be around A$1.8 billion in 2012/13 and A$1.9 billion in 2013/14.