Air New Zealand will help transtasman passengers affected by the grounding of the Qantas fleet.
Australasia general manager Bruce Parton said the airline was working to free up 6-8 aircraft and organising cover for baggage-handling duties.
Qantas grounded its fleet yesterday (Saturday), forcing the cancellation of almost 450 flights and affecting about 80,000 passengers.
The airline says it made the move in preparation for a lockout of about 6000 employees covered by collective employment agreements.
Transtasman flights have been largely unaffected because Auckland-based Jetconnect runs the flights under the Qantas brand.
But Mr Parton said putting on extra Air NZ planes would allow its partner Virgin to divert aircraft to Australian domestic routes in a bid to limit disruption ahead of Tuesday's Melbourne Cup.
Mr Parton flew to Sydney this afternoon to work on contingency plans. He said the airport's Qantas check-in area was "utter chaos".
"It's 20 feet deep with people screaming and yelling. There's a lot of anger and angst, the customers are pretty unhappy with how they've been treated.
"When I'm talking to the Qantas customers, what they're staggered with is the speed at which this was bought in. No one got any warning ... They just feel like they've been treated with disdain."
Although Qantas staff have been working today, the lockout will bar pilots, ground staff and baggage handlers, among others, from working.
Mr Parton said Air NZ had no warning the "unprecedented" move was coming and said it would do long-term damage to the Qantas brand.
"Both across the Tasman, and domestic, people have very long memories and if you treat them in the way in which they've been treated in the last 24 hours, they'll certainly remember."
Emergency discussions between Qantas and Fair Work Australia, the national workplace relations tribunal, resumed in Melbourne this afternoon at the request of the Australian Government.
A Qantas senior executive told the hearing he had to ground the airline's fleet for safety reasons after the decision was taken to lock out workers.
Lyell Strambi, who is responsible for the airline's Air Operator's Certificate, said long-running industrial action by the unions had resulted in a gradual increase in risks on safety.
Mr Strambi said Qantas received a letter from the Civil Aviation Safety Authority (CASA) on October 14, outlining their concern over the impact the action was having on fleet safety.
Qantas had three options available, negotiating in good faith, capitulating, or taking protected industrial action of their own.
He said he took the decision to ground the airline's fleet after chief executive Alan Joyce decided the airline would take protected industrial action in the form of a lockout.
Under cross-examination by Arthur Moses, SC, for the Australian and International Pilots Association, Mr Strambi said based on advice he had received, it would be unsafe for the airline to continue operating during a 72-hour notice period before the lockout because of concerns regarding fatigue and distraction among staff.
Mr Strambi said the airline had to step in and take action before CASA did.
"We would not wait for the regulator to ground us," he said.
"My first obligation is to the safety of this organisation ... at that point in time, we were in a very risky situation."
Mr Moses said he would propose a 120-day suspension of industrial action to allow negotiations around pay and conditions to continue.
But Qantas chief executive Alan Joyce told Sky News the airline's unions would have to terminate industrial action to get the fleet back in the air.
He said a suspension was not enough because the option lacked certainty.
If a termination was ordered, Mr Joyce said the airline needed to go through a process with CASA which could take a few hours.
It could take another six hours to get the fleet flying after approval was given, he said.