Former prime minister Helen Clark says incoming Prime Minister Jacinda Ardern has proven she has backbone and steel.
Speaking to Checkpoint via Skype from London, Miss Clark - who served as leader for almost nine years from 1999 to 2008 - said they had not spoken yet but had been in contact online.
Ms Ardern had done a phenomenal job, she said.
"She was thrown a pretty curved ball back when Andrew Little stood down and she was unanimously selected as leader.
"It looked like mission impossible and I guess at the time she thought 'well I can save the party from a crushing defeat but how far can I take it?'
"And actually she took it all the way to quite a credible result."
Miss Clark said the support Labour gathered in a matter of weeks and then to negotiate a complex agreement showed considerable skills.
"I think she's got the making of a good term of government in her.
"I think that Jacinda is characterised by enormous empathy. She exudes empathy, and she's a very very good communicator. People very much feel that Jacinda is interested in them, she's interested in their families, she is interested in how they are doing, she wants to make a difference for people.
"She's very motivated by that and I think people warm to her because she is warm as a personality and can communicate that warmth.
"I think she's shown she's also got backbone and some steel.
"Look, empathy's an incredibly important thing ... but also to have backbone, to be firm when you have to be firm. Consult, include, but be firm."
Miss Clark said it was not only New Zealand breaking the mold, as young leaders have risen to power in Canada, France, and Austria.
"We're in a new age.
"I don't think this could have been done in my time but I think people are much more open now to young people coming forward and doing their best."
Miss Clark also said she had worked well with New Zealand First leader Winston Peters, when he was Minister of Foreign Affairs.
"I worked with Winston Peters very closely for three years and I have to say when he gave his word on the formation of the government that word was never broken and it was a harmonious working relationship."
