Analysis: Todd Muller delivers conciliatory, statesmanlike speech - but it will take more to beat Jacinda Ardern

New Opposition leader Todd Muller delivered a conciliatory statesmanlike speech on his first day as National's leader - but it will take a hell of a lot more to beat Prime Minister Jacinda Ardern.

Ardern took over the Labour leadership six weeks out from the last election - and look at her now. Muller even kind of compared himself to her - raising the spectre of that moment.

He called the Prime Minister "impressive", "approachable" and a "tremendous communicator".  That speaks to the tone he is setting for himself as leader - he went for a conciliatory, statesmanlike speech.

But it's going to take more than that to go from being someone few people have heard of, in a party destroyed in the polls - to someone who can take on a Prime Minister as popular as Ardern.

He won a battle today - but the campaign war has just begun.

Muller is MP for the Bay of Plenty and a former businessman who's promising to bring a new style of politics to Parliament.

His deputy is Auckland Central MP Nikki Kaye who has taken former deputy leader Paula Bennett's job. Kaye is there to provide a liberal balance to Muller's conservatism.

Muller started the day with an understatement: "I'm feeling very excited - a momentous day for the National Party."

He walked into Parliament and caucus not well-known and walked out as leader of the biggest political party with his new deputy leader in tow.

Kaye described him as the "probably the most decent person I know".

Whoever he is, Muller pulled off an incredible coup, rolling former National leader Simon Bridges just months out from an election and rolling out a team of key players for his opening gambit.

When Newshub asked Muller why he rolled Bridges and what was wrong with his former boss's leadership, Muller said, "This was a caucus conversation".

Bridges might argue otherwise - a brutal backstabbing to end his fraught two and bit years in the toughest job in Parliament.

"I can't say I've enjoyed every minute of it, but I almost have," Bridges said. "It's been a blast - I've got absolutely no regrets."

As they piled in behind the massive blue National Party banner at midday on Friday, National MPs were picking a tight fight for the leadership. But Muller was tight-lipped on how the vote went.

"The caucus votes, we have no idea what numbers, we never do," he said.

Newshub asked Muller if all the MPs standing on stage behind him supported his bid for leadership.

"It's a secret ballot," he replied. "We had a fantastic caucus, very respectful."

Again, that's probably not so much from Team Bridges' perspective.

"Well look, obviously disappointed but it's a funny old thing. There was also a bit of relief," Bridges said.

Muller is clearly setting himself apart from Bridges, particularly with one very pointed dig at the former leader.

"First and foremost, I'm about what's best for you and your family - not what's wrong with the Government," Muller said. "I'm not interested in Opposition for Opposition's sake. We're all tired of that kind of politics."

The leadership came down to a race between someone the country doesn't like - Bridges - versus someone the country doesn't know - Muller - but that all changes now.

"I'm really hopeful that I'll be in the news tonight - so that might start it," Muller said.

Muller is socially conservative. He voted against abortion and euthanasia.

"My perspective when it comes to social issues are informed by my Catholic faith," he said.

Under his leadership, National working with New Zealand First leader Winston Peters post-election could be back on the table after Bridges ruled it out.

But Muller would not give much away.

"I appreciate I'm the leader but we have been here for two hours," he said, when asked if working with Peters is something National will now consider. "In my opinion, lots of things change post-COVID."

Things changed so much for Bridges that he walked into work on Friday morning a leader convinced he would walk out one too, but left without even an offer of a seat on Muller's front bench.

Asked if he would give Bridges that honour, Muller said: "That's a conversation for another day."

It's one of many big decisions ahead for National's new chief.

"There's not been 48 hours like it for me personally," Muller said, reflecting on the tumultuous morning. "It's been pretty full-on."