Prime Minister Jacinda Ardern has met Former US President Barack Obama for the first time at Auckland's Government House this afternoon.

The two shook hands and performed a hongi with each other after a stirring powhiri greeted Obama onto the grounds.

Obama was presented with a traditional carved whalebone necklace and one to take home to his wife Michelle.

Obama's trip now turns from a golfing one to a more formal affair as he attends a gala dinner in Auckland tonight, where he will address a crowd of around 800 people.

He is also set to meet Prime Minister Jacinda Ardern in a closed door meeting.