COMMENT: Much has been made of English and Bennett's polarities - man and woman, Aucklander and South Islander, quiet and loud, solo mum and family man.

Simon Bridges has withdrawn from the contest to be National's deputy leader today - handing it to Paula Bennett.

The advantage Bill English has when he forms his new Government next week is that he won't be burdened by high expectations.

Reputation studiously rebuilt after a political mauling 14 years ago, the new PM now has chance to right the record, writes Claire Trevett.

COMMENT: As we farewell a gifted PM we are about to get a more combative one. John Key's politics have been emollient, Bill English is abrasive.

Paula Bennett is a handful of votes away from becoming New Zealand's Deputy Prime Minister.

New Zealand's new Prime Minister is a former farmer and literature student from smalltown Southland who once described himself as "specialising in being boring".

Incoming Prime Minister Bill English has confirmed that Wayne Eagleson will remain in the influential position of the prime minister's chief of staff.

COMMENT: For a decade National didn't have to think about a leader, now they will be scrambling to make sense of it all, writes Barry Soper.

COMMENT: 'The personal is political": a slogan that John Key, our outgoing Prime Minister, fudged vigorously throughout his tenure.

Judith Collins has laid out her policy agenda if she is elected Prime Minister.

The National Party is inviting Kiwis to thank John Key for his 10 years leading the party and eight years' service as Prime Minister.

Fevered lobbying to become the next PM has begun in the National caucus as Bill English, Judith Collins and Jonathan Coleman vie for position.

COMMENT: I'm not gonna lie. I'm glad to see the back end of him. Clothed, of course, writes Rachel Stewart.

COMMENT: National MPs should think twice before automatically anointing as prime minister a member of Key's kitchen cabinet, Fran O'Sullivan writes.

National Party politics - and, by extension, New Zealand politics - have suddenly become very uncertain.

The contest for New Zealand's next PM is shaping up as a race between an veteran politician, a lower-profile minister, and a wild card.

Leadership contests are usually damaging for political parties - but National's will be mercifully brief, writes Audrey Young.

COMMENT: Having ticked all the boxes John Key leaves at the peak of his popularity and powers. It doesn't get any more impressive than that.

The cohesive National Party caucus that John Key has led for 10 years is about to start fraying as members grapple with how to replace him as PM.

John Key's bombshell announcement yesterday has thrown New Zealand politics into turmoil.

Labour appear quietly thrilled about the prospect of a National Party without John Key.

COMMENT: If there were family reasons for John Key's decision to stand down, they were surely the demands of his art-school daughter or YouTube son.

Key says there is no secret scandal behind his decision to resign, saying he wanted to rewrite the rule book on leadership departures and do so on his own terms.

National faced a more uncertain future without Key at the helm, says University of Auckland political scientist Raymond Miller.

COMMENT: Winning that elusive fourth term in office has just become much harder, writes Newstalk ZB's political editor Barry Soper.

His body language suggested he was speaking honestly, an expert says.

Bill English is staying silent on whether he wants to be New Zealand's next Prime Minister and Judith Collins has not ruled out a bid to replace Key.

Leader of the Opposition Andrew Little has paid tribute to outgoing Prime Minister John Key, saying he has "served New Zealand well".

John Key's shock resignation has resonated around the globe with media and leaders from Australia and as far afield as China, the United States and Russia and France broadcasting the news online.