The changes come after the airline last month gained prized slots at Haneda at times convenient for business travellers. Qantas will operate an Airbus A330 four times a week between Brisbane and Narita and use a larger Boeing 747 for the Sydney-Haneda flights.

Qantas also said it would shortly add services from another Australian airport to Narita.

Melbourne, which has four weekly Jetstar flights to Narita, is among the more obvious options to receive three flights per week to Japan from the mainline division.

In total, Qantas will add more than 4000 seats per week to Japan as a result of the changes. Departures from Australia to Japan have risen by 17 per cent over the past year.

Qantas on Monday told the market its international division was expected to report positive earnings before interest and tax in the first half of the financial year. That is a major turnaround considering the business lost about $500 million of EBIT last year.

Qantas chief executive Alan Joyce attributed the reversal in fortune to a series of initiatives.

Depreciation charges will fall by $200 million this year after the airline wrote down $2.6 billion of the value of the fleet in August. The airline has also increased the number of hours it is flying its aircraft and has changed its frequent flyer program to encourage travellers to book on Qantas flights and in higher fare classes.

Mr Joyce announced the changes to the Japan flying schedule during a tour of the airline's Brisbane heavy maintenance facility with Queensland Premier Campbell Newman on Tuesday. The facility is being used to refit Qantas' fleet of A330 aircraft with new interiors, including fully flat seats with aisle access in business class.

"We're proud to be doing work on our A330s in Brisbane, where we have more than 200 engineers and support staff working for 30 days on each aircraft to install 250,000 individual parts," Mr Joyce said. "When the project is finished by the end of 2016, we believe these aircraft will offer the best travel experience between Australia and Asia and the best domestic travel experience anywhere in the world."

The first domestic A330 with the new interiors will enter service this month on the Sydney-Perth route. The first international A330 will enter service in mid-January on the Melbourne-Singapore route. More than half of the A330 fleet is expected to be refurbished by the end of December 2015.

Tickets for the new Sydney-Haneda and Brisbane-Narita services will be available progressively from later this week. The first Brisbane-Narita flight will be on August 1 and the first Sydney-Haneda service will be on July 31. Jetstar offers daily flights from the Gold Coast to Narita.