Bill English, Paula Bennett vow to take the job seriously

New Prime Minister Bill English has been sworn in as Prime Minister and his first job will be to reshuffle his caucus before Christmas.

English and new Deputy Prime Minister Paula Bennett were formally appointed at a ceremony in Government House in Wellington this afternoon after earlier getting the backing of their caucus.

In a brief ceremony, English promised Governor-General Dame Patsy Reddy to "take seriously the job you have conferred on us".

English is expected to announce a new Cabinet lineup in the next week.

In a press conference following his appointment as National leader, English gave an outline of what his Government will look like, saying he will deliver "smarter" ways to help the most vulnerable.

He indicated infrastructure would be a priority, saying the Government would continue to invest in roading, public transport, schools and housing.

However, he refused to commit to former Prime Minister John Key's 2008 promise not to change the pension age, saying it would be among a stocktake of National's policies that would take place before the 2017 election.

On other issues, he ruled out a shift to a republic and but would not rule out a knighthood for Key, joking: "Well, it's not as if he's never asked".

Paula Bennett and Bill English. Photo / Mark Mitchell

On his first day in charge, English was urged to show some early leadership by speaking with families of victims from the Pike River Mine disaster.

Some of the families will protest outside Parliament tomorrow, urging the Government to prevent mine owner Solid Energy from sealing the mine and allowing re-entry to recover the bodies of 29 dead.

English said he would not meet with the families tomorrow, but might do so at a later date.

The new Prime Minister also ruled out an early election. Labour's Andrew Little has proposed an early election to avoid a series of by-elections, but English said this was not a good reason to bring the polls forward.

Little, while congratulating the new leadership team, linked English and Bennett to some of the problems he said the Key-led Government had created.

He questioned whether Bennett "truly represented something different" and said they would struggle to "shake off responsibility" for issues such as falling home ownership rates.

Little also said English was out of step on issues such as euthanasia.

English, a practising Catholic, opposes the legalisation of voluntary euthanasia and has spoken against abortion.

However, he revealed today he no longer opposed same-sex marriage, which he voted against in 2012 - a stance which was immediately welcomed by the Human Rights Commission. English also said he would not use his Prime Ministerial role to push for socially conservative changes.

After her appointment, Deputy Prime Minister Paula Bennett spoke of her rise from a solo mum on a benefit to the second-highest job in Government, saying her ascent was "a credit to this country". There were opportunities for people who wanted a second chance in New Zealand, she said.

Bennett, who is known for her colourful dress sense and larger-than-life personality, said she would not become more serious in her new role, but she would take the job seriously.

Bill English farewells Prime Minister John Key and his wife Bronagh. Photo / Mark Mitchell

Before English and Bennett were formally sworn in, National MPs farewelled Key with a guard of honour on Parliament's steps. Some of Key's staff and MPs cried as he left Parliament for the last time as Prime Minister.

Key told reporters he looked forward to being "anonymous" but also spoke candidly about his need for public approval while he led the country.

"Truthfully, I'm the kind of person that likes to be liked," he said.

"And most people are, but I'm particular of that sort of nature."

Asked for a piece of advice for English, he said: "Trust your instincts".