Prime Minister Jacinda Ardern has been a trail-blazer for female politicians in her nine-year career in Parliament - which was capped when she was sworn in as Prime Minister last week.

She became the youngest-sitting MP when elected in 2008, is the youngest ever Labour Party leader and the second-youngest leader of New Zealand's Parliament. And the accolades continued this week when she was ranked in 13th spot on Forbes' latest 'Women Who Rule the World' list.

Now Ardern, and the rest of New Zealand, are set to learn a bit more about trail-blazers in the rest of her family in Tuesday night's season premiere of The DNA Detectives on TVNZ 1.

"I think almost everyone out there has some kind of family secrets that mean you have these bits of a puzzle in your family history that you can't solve," Adern said ahead of the show.

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"Being able to piece together who you are and where you're from is really important."

Ardern went onto the show knowing she had Scottish ancestory on her mother's side.

Her nana's house was adorned with tartan patterns and photos of castles. Tins of shortbread were always on hand.

"The Scottish part of my family has always been so strong, in a large part because of my nana," Ardern said.

Producers Jam TV were tight-lipped ahead of the show about all of its contents, but did confirm that they had been able to trace back a family member on Ardern's mother's side who had worked for Queen Victoria.

The Prime Minister was also able to discover she had a number of war heroes in her family.

The show also discovered how Ardern's maternal great grandmother had been ahead of her time when it came to advancements in car technology.

"Jacinda's maternal great grandmother hated getting her hand wet while indicating in her old Ford so wrote to the Minister of Transport with an idea for an automatic traffic indicator controlled from inside the car," production notes from Jam TV revealed.

"He wrote back suggesting she patent her idea. Sadly she didn't, and the Ford company eventually came up with their own design."

Ardern said she went onto the show realising "that maybe in your DNA something really sparky or interesting will spring up".

And it sounds like like TVNZ's DNA detectives didn't disappoint.

•The DNA Detectives returns on TVNZ1 on Tuesday night at 8.30pm