Jacinda Ardern is the most charismatic politician in the world, it has been claimed.

Ms Ardern is "something special, and everyone sees it" political strategist John McTernan told The AM Show on Thursday.

Mr McTernan was director of operations for UK Prime Minister Tony Blair in the mid-2000s, and has worked for the Australian and Scottish Labour parties, including as director of communications for then-Australian Prime Minister Julia Gillard.

He was on The AM Show to discuss the rise of populism - a political view that backs the will of the majority against the so-called 'elite', often with a charismatic figurehead who promises to fix society's problems. In Donald Trump's case, for example, that would be by "draining the swamp".

Recent examples of leaders labelled populist include figures from both the left and right, such as Brazil's Jair Bolsonaro, the UK's Jeremy Corbyn and New Zealand's own Winston Peters and Robert Muldoon.

Mr McTernan said the present-day resurgence of populism is the result of the global financial crisis, and how governments around the world responded.

"The bankers nearly crashed the global economy, they got bailed out with taxpayers' money all across Europe and the US.

"No one went to jail, and most people around the world - most working people - have had a pretty hard decade. They haven't had a pay rise for 10 years. They're looking for somebody to blame, and they're looking for somebody more importantly to offer them hope for the future - that's where the populist figure steps in and says, 'I can give you a better future.'"

But there's a difference between populism and what Ms Ardern has to offer, he says.

"You're very lucky in New Zealand. Jacinda is probably the most charismatic single figure, democratic leader in the world at the moment. It's not just that she's popular - it's that she is something special, and everyone sees it. She's fresh, she's a star, she's the real thing.

"When she talks about things, people listen to her - they go, 'Okay - I get that it's going to take a long time to turn around the economy, it's going to take a long time to turn around the infrastructure, to invest in the transport we need, it's going to take a while build up KiwiBuild. But she's got a plan.'

"When people listen to her, they go, 'Alright, you've thought about this - you've got a plan. I trust you to do it.' I think trust is one of the biggest elements in politics. It's the lack of trust, the erosion of trust, the corrosion of it - you see it in American politics, the polarisation."

Until she came along, Mr McTernan says Canada had the world's most charismatic leader.

"But she beats Justin Trudeau into a cocked hat."

Among Kiwis, Ms Ardern topped the latest preferred Prime Minister poll.