The former Wales coach will take the reins as the Chiefs head coach next season in the first year of a contract that will see him with the club until the end of 2023.
However, he will take time away from the team in 2021 to coach the British and Irish Lions, before returning to the helm.
New Zealand Rugby chairman Brent Impey said last week that 26 top New Zealand coaches had been approached to apply for the All Blacks head coach role.
Gatland has told the Radio Sport Breakfast he had to say no to New Zealand Rugby.
"I was contacted about that…it was nice to be contacted I politely declined putting my name forward," Gatland said this morning.
"I'm a little bit old school…I'd made the commitment to the Chiefs and I'd made the commitment to the Lions, it was important that I carry on with that…honour the commitment I made to those two sides.
"Maybe sometime in the future I may get that opportunity again," he added.
Gatland said if the chance to coach the All Blacks never arose again, he wouldn't have any regrets.
"No it's not something I think about," he told the Radio Sport Breakfast.
"I'm not one of those people who plan ahead too much…I'm a great believer in what will be will be. For me having been away a long time there are a lot of different challenges and the challenges are to kind re-integrate myself back into New Zealand rugby.
"If you are successful other opportunities will come along. It was time for me to make a decision to leave Wales and the northern hemisphere and come back to New Zealand and I'm excited by that," Gatland said.
