Prime Minister Jacinda Ardern has used a popular US TV show to invite comedy duo Flight of the Conchords over for dinner.

Appearing as a guest on the Late Show with Stephen Colbert, Ms Ardern also extended the popular TV host an official invitation to become a citizen of Hobbiton.

After grilling New Zealand's leader about US President Donald Trump being laughed at by United Nations diplomats a day earlier, Colbert played her a video of Bret McKenzie and Jemaine Clement from the previous episode of his show.

"Hey Jacinda, we have an important question for you. Can we come for dinner?" the Flight of the Conchords stars asked in the clip.

Ms Ardern said she was happy to have them over for dinner "if they pick me up from the airport".

"I've met them before. It's New Zealand, so we all know each other."

Colbert is a renowned fan of Sir Peter Jackson's The Hobbit and Lord of the Rings trilogies and, of course, steered the conversation in that direction as soon as he could.

"You have an impressive resume, but perhaps most impressive to me is that you could technically be described as a hobbit. I understand you grew up near Hobbiton?" asked Colbert.

"I did," responded Ardern, before adding, "I do find it slightly offensive that everyone think that every New Zealander starred in either Lord of the Rings or The Hobbit."

Without missing a beat, Colbert then asked, "Were you in Lord of the Rings or The Hobbit?"

"Some of us auditioned but weren't successful," said Ms Ardern.