Air New Zealand said the US Department of Justice has dropped the airline from its investigation into cartel behaviour in the air cargo market.

The national carrier, which is about three-quarters owned by the New Zealand government, said it has spent five years defending itself.

US Department of Justice Federal Prosecutors confirmed by letter that they have ended their investigation and Air New Zealand "is no longer a subject or target of the ongoing grand jury investigation," the company said in a statement today.

Air New Zealand has also escaped censure from the European Commission and South Korean regulators, which omitted the airline from a list of rivals fined for a role in a cartel.

Competition regulators around the world commenced investigations into the air cargo industry in 2005 and fines imposed to date exceed US$1 billion, the airline said in its statement.

"Air New Zealand welcomes this further step as it continues to demonstrate its innocence in respect of the cartel allegations," said general counsel John Blair.

The airline is still under investigation in New Zealand.