Qantas is not backing down from its promotions in the UK where it claims to be "the world's most experienced airline" despite being investigated by Britain's advertising watchdog.

The UK's Advertising Standards Authority (ASA) has received eight complaints about a series of print and television ads for the Australian airline which ran in Britain earlier this year.

Qantas executive general manager John Borghetti is standing by the carrier's assertion that it is the world's most experienced airline.

"Not only has Qantas been in full operation longer than any other airline in the world but the depth and breadth of our experience as a long-haul carrier backs this up," Mr Borghetti said.

"We are defending our assertion that Qantas is the world's most experienced airline."

Qantas has been flying continuously for 87 years, was the first airline to introduce business class in 1979 and, in 1958, became the first to fly around the world.

The ASA's investigation is expected to be completed in the next few weeks.

However, the ASA is not a statutory authority so is unable to do much more than give Qantas a public slap on the wrist if it finds the airline's claims are misleading.