Jacinda Ardern's staff purchased commercial ticket in case Defence Force plane broke down

Jacinda Ardern's staff purchased a commercial airline flight ticket for her in case the Defence Force plane taking her home broke down in Melbourne - and it did. 

The Prime Minister was stuck in the Australian city Friday evening after the Defence Force Boeing 757 plane taking her back to New Zealand broke down. 

Ardern took a commercial flight back in the evening, while journalists covering her trip were left stranded. 

"I do apologise to those who got away late because of that," Ardern said on Monday. 

The plane had broken down ahead of her trip too, which the Prime Minister said prompted her staff to purchase her a commercial ticket back home in case it broke down again. 

"There were issues with the 757 prior to our departure so that was based on there already having been an issue with the 757 before we left," Ardern said. 

"Naturally, you would expect that would be the wise thing to do in the context of that time when there had been issues, and we knew that.

"That was the reason why we did. I don't believe that we do that routinely, though, but we did on this occasion because of that issue."

Ardern said there "will be occasions when there are engineering issues with our 757s, as there are from time to time for commercial airlines". 

Defence Minister Ron Mark told NZME there are no imminent plans to replace the 757s. They are due to be replaced in 2028.

The Defence Force has two 757s used for transporting VIPs. They were purchased in 2003 for $221 million.

The planes have a history of breaking down. Former Prime Minister John Key had to be rescued back in 2016 when a 757 broke down twice, stranding him and a delegation of nearly 100 in Townsville, Australia en route to India.

Last month, a second plane had to be sent to pick up Deputy Prime Minister Winston Peters when one of the 757s broke down in Vanuatu.