The softening of Bill English's image is going into overdrive in election year. But the Prime Minister is still far from comfortable in the public gaze, one expert says.

Like John Key and Helen Clark before him, English has set about revealing more of his personal life in a bid to become more relatable to the voting public.

Earlier this week, there was the selfie of a family dinner and his unconventional pizza-making method - a stunt which generated headlines overseas.

That was followed by a more slickly-produced promotional video on Facebook today which features the Prime Minister, sleeves rolled up, playing cricket and reading stories to children.

Since taking on the top job in December, English has also hosted media in his hometown in Dipton, and given a series of breezy interviews alongside deputy Paula Bennett where they talked about their favourite karaoke tunes.

Massey University political scientist Claire Robinson, who specialises in political messaging, said English had been forced to quickly build up a public brand after eight years in the background as Finance Minister.

"English is still trying to find out his public persona," she said. "Because it's not a comfortable place for him. I think he's much more comfortable working behind the scenes.

"He seems to be enjoying the more public aspects of the role, and I think that when you see the photographs of him he seems to be genuinely enjoying it.

"But I think he's still trying to work out what works for him."

His best publicity stunt was the sheep-shearing competition against champion shearing legend Sir David Fagan.

"It was unique," Robinson said. "You wouldn't get John Key trying to shear a sheep like that. It showed that he was good at something other than being a politician. And that felt quite natural, in the sense that he comes from a farming community in the deep south."

The spaghetti stunt was also a surprise hit, she said: "I think he chanced upon it, but it wasn't a fail."

English insisted yesterday that it was a spirit-of-the moment thing, and not a stage-managed affair.

"It was spontaneous. I was dared by one of my kids."

Asked whether he was uncomfortable with the new demands of being Prime Minister, he said: "No, I just realised that there's a personal aspect to the role.

"People like to know who the person is, which is different from reducing your privacy."

The timing of English's rise to the top job is significant. His predecessor, Key, had two years as Leader of the Opposition before he came to power, giving him time to build up a relationship with the public before he took top office.

English has had to hit the ground running, less than a year out from an election.

When Key was elected Prime Minister in 2008, social media and smartphone technology was still in its infancy, and Key gradually learned to use it to his advantage. Nine years later, English has been forced to play catch-up on the quickly-changing social media landscape.

His opponent, Labour leader Andrew Little, is similarly adjusting to the public demands of leadership.

The former unionist has the advantage of a soft media-savvy deputy, Jacinda Ardern, who makes regular magazine appearances and commands 63,000 followers on Twitter (four times as many as English and five times as many as Little).

The two appeared on the front cover of the New Zealand Woman's Weekly this week, under the tagline: "Our Special Bond: Jokes, roads trips, and whisky sessions".

Little this week referred to their promotional work as the "Jacinda and Andrew Show", before remembering his seniority and quickly correcting it to the "Andrew and Jacinda show".

Key, who mastered the art of soft media, also found that it had pitfalls. He scaled back his commercial radio appearances after an incident on The Rock radio station when he was made to participate in a prison rape joke (which he plead innocence to).

He also set a difficult example for his successor by enthusiastically taking on all subjects and questions from media, no matter how light or obscure.

That is something English is still grappling with, as was evident when he awkwardly dealt with softball questions about "spaghetti-gate" at Parliament yesterday.

"It seems to have divided the nation," he said, a little bemused at the attention.

Why did he post the selfie?

"Just thinking it would be interesting to see how people reacted to me cooking a pizza," he said.

So what is an expert's advice for the Prime Minister?

"To look slightly more Prime Ministerial," Robinson said.

"He naturally doesn't like to wear a jacket, he likes to look like he's getting down and into it with his shirtsleeves rolled up.

"It is a really important for people to get to know Bill, to know that he has a softer side and is not just a flinty Finance Minister. But it's a fine balance that he has to strike between looking Prime Ministerial and looking like an ordinary bloke.

"He's probably erring too much towards the ordinary Kiwi bloke at the moment."

-NZ Herald