A fault in the system was noticed about noon on Friday. It couldn't be rectified by yesterday morning and a prolonged bout of fog led to major disruptions.
Air traffic control agency Airways New Zealand said it was the first time the system had failed since it was introduced five years ago.
"An intermittent fault within the ILS was discovered and a team of engineers began working on the problem," said spokeswoman Philippa Sellens.
"When fog came down at Auckland Airport early yesterday a decision was made to stop landing planes there until it was fixed."
Many passengers at the airport were annoyed but remained philosophical about the lengthy disruptions.
Shane Baylis, 24, and his partner Hayley Kirton, 25, arrived at 5am on an Air New Zealand flight from Perth, Australia. The couple was due to catch a connecting service to New Plymouth at 10.30am, but it was delayed indefinitely.
"We are here to visit my family and after a 6 hour flight from Perth this was the last thing we needed," bleary-eyed Baylis said.
"But it isn't as bad as when I made the same journey last year and was stranded in Auckland for three days because of a volcanic ash cloud from Chile."
Seven-months pregnant Sopharina Lang opted for a nap while trying to get home to Nelson with her husband, Vannak Heng, and their young son. They were returning from visiting Heng's family in Cambodia.
By lunchtime yesterday services resumed and airlines were catching up on their backlog. However, the ILS was still being repaired and a spokesman said passengers should check with the airlines before travelling, in case of more fog.
