Underlying pre-tax profit for the six months to December 31 soared 14.6 per cent to a record $976 million, although net profit fell short of 2016's record $688 million due to $119 million of costs including redundancies and the introduction of the Dreamliner aircraft.

Nonetheless, Qantas will pay an unfranked interim dividend of seven cents and says it will buy back up to $378 million of shares, which will take the total spent on buybacks since 2016 to $1.617 billion.

Chief executive Alan Joyce says the transformation of Qantas during his tenure - which has included hefty redundancies, route changes and aircraft retirements - has left the airline well placed.

He says Thursday's first-half result includes $181 million of benefits from the transformation program, with a full-year target of $400 million.

"After several years of consistent performance, we now have a lot of momentum behind us," Mr Joyce said in a statement.

"We're vigilant about maintaining that momentum and we're confident about the future it allows us to build."

Net passenger revenue rose to $7.493 billion from $7.064 billion in the prior corresponding period, while freight revenue jumped to $440 million from $416 million.

Australian Associated Press