Jacinda Ardern's leadership ambitions 'hypothetical' - Andrew Little

Labour leader Andrew Little denies it's only a matter of time before his deputy, Jacinda Ardern, outshines him.

Asked on The Nation what will happen 'when' she surpasses him in the polls for preferred Prime Minister, Mr Little said he wasn't "going to buy into that".

"You're talking hypothetically and you're speculating and so on," he told host Lisa Owen.

Ms Ardern rated 4.2 percent in a poll last year, Mr Little not far ahead on 8.9 percent. The difference is he was leader then, and being deputy was still a twinkle in Ms Ardern's eyes.

Even now that she's replaced the retiring Annette King, Mr Little still thinks his job is safe.

"Jacinda and I work very closely together. We've established - we've always had a good working relationship. We've just had a great week together getting out and about.

"We'll be getting out and about a lot more, and we are talking about what matters to New Zealand and fixing the problems."

Newshub political reporter Lloyd Burr's experience at Victoria University earlier this week backed Mr Little's belief he's the man to lead Labour into the election, with few students at the left-leaning campus knowing who Ms Ardern was.

"Andrew Little, on the other hand, was recognised by almost everyone," Burr wrote.

He asked 17 students if they knew who Andrew Little was. Nine knew he was leader, five knew he was a Labour MP and three had never heard of him.

Ten had never heard of Ms Ardern, five knew she was deputy, one thought she was co-leader and the last knew she was an MP, but wasn't up with the news of her promotion.

"It's great that we've got Jacinda up as deputy and we've got a great team behind both of us and we're all campaigning very hard," Mr Little told The Nation.

"What matters most to New Zealanders is whether we are the party with a plan to fix the problems that New Zealanders have got. That's what we're campaigning on."