Clarke Gayford has joked that he is "punching above his weight" in his relationship with New Zealand Prime Minister Jacinda Ardern.

Gayford hosts fishing program Fish of the Day and shared some insight into his relationship with Ardern.

He answered a question about how their relationship began on Australian radio station Nova 96.9.

"I thought you were about to accuse me of punching [above my weight], and, well, you would be right!" he joked.

Gayford explained to hosts Fitzy and Wippa that he met his now-fiancee through official channels.

"This is slightly embarrassing, I had a constituency issue and I emailed my local MP and I got some really good advice," he laughed.

The pair briefly met for the first time at an awards show in 2012, with Gayford reaching out to Ardern to discuss his concerns over a proposed bill.

The pair's relationship became more high-profile in August 2017 as Ardern became the leader of New Zealand's Labour Party. Just seven weeks later, she was elected to the office of Prime Minister.

Gayford remembers that moment vividly.

"As I was about to go down underwater I turned my phone off, like 'I don't want to know about this'," he told Nova's Fitzy and Wippa.

"When I came back up the guy on the boat said, 'Yeah, mate, you might want to call back home. Your missus has had a promotion'."

Gayford was diving in Queensland and was filming the new Discovery Channel documentary Shark Lockdown when Ardern was made Prime Minister.

The pair are now engaged after having their first child, daughter Neve Te Aroha in June 2018.