Air New Zealand customers trying to visit sick relative on hold for more than 30 combined hours after flight overbooked

A US-based couple says they spent more than 30 hours on the phone trying to fix major travel bungles after one of their flights en route to New Zealand was overbooked - something they were only told when they arrived at the gate.

It comes amid major disruption to flights with multiple delays, cancellations while Air New Zealand's phone lines have been bombarded. 

People have been struggling to manage their plans due to massive travel demand as the school holidays got underway, bad weather and staff illness.

In call centres, there have been reports of people waiting up to four hours to speak to someone - only to be "hung up on". 

Treasure Alvarez-Connors and husband Josh Connors-Wilson, from Seattle, booked flights for themselves and their baby to Christchurch through Air New Zealand to visit a terminally ill relative.

They were booked to fly from Seattle to Vancouver, then Vancouver to Auckland on Air Canada - an Air NZ partner airline.

But Air Canada oversold the flight, something the family wasn't told until they arrived at the gate. As a result, Josh didn't have a seat and the family was forced to split up.

Josh was told to contact Air NZ and waited 5-and-a-half hours on the phone. 

The couple said Air NZ nor its partner airline would accept accountability for the mistake.

"No real solutions were actually coming to the table," Treasure told AM.

Josh eventually got to Christchurch more than a week after his wife and son, travelling from Seattle via LA and Fiji.

To compound the arriving flight debacle, those problems extended after Air Canada took Josh off the original booking for their return trip - forcing him to rebook the flights which proved a nightmare due to availability.

That meant more time on the phone with Air NZ. In total, Josh told AM host Ryan Bridge they have been on hold for about 35 hours over a three-week period.

"It's not great circumstances and it's kind of comical for us - our longest [wait time] was six hours being hung up and we're actually sitting close to about the 35-hour mark," he said.

Treasure said the matter was finally sorted and they are due to begin their return trip home on Sunday - but she was sceptical.

"Even now, we're still pretty hesitant to believe that it is sorted because we've had flight confirmations from Air New Zealand before and that clearly didn't work out."

The couple's advice to travellers was "if you think you've given yourself enough time, you haven't".

"We got to the airport four hours before our flight and, still, only half of our party made it," Treasure said. "Just assume the time that you've allotted is not going to be enough, especially with the holiday travellers and weather, and travel in general, as we're seeing around the world, is insane right now - just give yourself as much time as you possibly can."

In a statement addressing the disruptions, Air NZ chief customer and sales officer Leanne Geraghty said its teams were working hard to address the disruptions.

"The airline is continuing to manage disruptions across our network due to wild weather conditions, employee sickness and engineering issues," she said. 

"Our teams are working around the clock to help ease these pressures and get our customers where they need to go."