Qantas planes will be able to return to the skies after Fair Work Australia (FWA) ruled to terminate an industrial dispute between Qantas and the unions.

The tribunal of judges retired for over two hours to consider whether to suspend or terminate the industrial action that triggered the saga.

In handing down the decision, Fair Work Australia accepted that the industrial action would have caused significant national economic harm.

In an unprecedented move, Qantas announced the immediate grounding of its entire fleet on Saturday ahead of a lockout of staff on Monday.

The deadlock has already affected more than 68,000 passengers worldwide and there were fears a failure to get planes back in the air quickly would damage the national economy.

The Federal Government had applied to the industrial umpire for the termination or suspension of industrial disputes between Qantas and three unions - Australian Licensed Engineers Union (ALAEA), the Transport Workers Union (TWU) and the Australian and International Pilots Union (AIPA).

After almost 14 hours of evidence over two days, the tribunal, headed by Justice Geoffrey Giudice, found there was significant uncertainty arising from the protected action of the unions but in particular from the Qantas employee lockout and grounding of the fleet.

"We should do what we can to avoid significant damage to the tourism industry," Justice Giudice said.

He said the unions had sought a suspension of the protected industrial action for up to 120 days but the panel had decided that such a move would not provide sufficient protection against the risk of economic damage to the tourism and aviation industries.

"Common Sense Restored"

In a press conference after the decision was handed down, Assistant Treasurer Bill Shorten said the Government was pleased with the decision.

"We are pleased after 24 hours of turmoil, common sense was restored," he told reporters.

"We believe now that Qantas and the unions will focus on getting flying as soon as they can."

Unions had wanted an 120-day suspension of all action, whereas Qantas argued for a lasting termination.

ACTU secretary Jeff Lawrence also responded to the ruling, calling for the Federal Government to ensure Qantas fulfils its obligations.

"We'll be working to make sure that those planes are in the air as soon as possible and that Qantas remains a good and viable airline that provides good jobs for Australian workers," he said.

"Fair Work Australia has recognised that it's the actions of Qantas that has the potential to cause harm to the Australian economy."

Qantas said it was losing AU$15 million per week due to months of strikes and other industrial action by unions.

Qantas says 447 flights have been cancelled, with furious passengers in major cities around the world vowing never to fly with Qantas again.

Qantas chief Alan Joyce, who ordered the lockout, made it clear he would not put his planes back in the air unless he had the "certainty" of a termination, not a suspension, of all industrial action.