Europe's third largest low-cost carrier has sent a letter to Norway's Civil Aviation Authority asking it to authorize "renting an aircraft that in all likelihood will be registered in the Irish Aircraft Registration Department".

The contents of the letter, seen by business daily Dagens Naeringsliv (DN), were confirmed to AFP by company spokesman Lasse Sandaker-Nielsen.

The new aircraft would operate on Norwegian's recently announced routes to Thailand and the United States.

To ensure competitive fares on the new routes, the company wants to hire staff in Asia for a fraction of the cost it is now paying in Scandinavia, but earlier this year Norwegian authorities ruled out making any changes to the existing framework.

The airline has responded by brandishing the possibility of registering eight future Boeing 787 Dreamliners abroad, adding to union allegations that it is practicing social dumping.

"A final decision has not been made yet," Sandaker-Nielsen said.

Norway airline carriers can only operate aircraft registered in another country on a temporary basis, and unless the rules are changed Norwegian would eventually have to register its entire long-haul subsidiary in Ireland, DN wrote.

Sandaker-Nielsen also said the company expects to take delivery of its first Dreamliner in June, almost two months behind schedule following problems with the planes' batteries that now appear to have been resolved.

Norwegian has previously said it would lease two Airbus A340s from Portugal's HiFly to avoid delaying the launch of its New York and Bangkok flights.