Bookmakers reveals odds on Judith Collins v Jacinda Ardern at NZ election 2020

Betting agencies are tipping Prime Minister Jacinda Ardern to retain her role as Prime Minister of New Zealand over new challenger Judith Collins.

Sportsbet, an Australian gambling site, has revealed its odds on next sworn-in government and the party seat totals for our general election on September 19.

Ardern's Labour is the clear favourite, paying $1.16 to be the party that supplies the Prime Minister, with Collins' National well behind at $5. Punters don't rate Winston Peters' chances of leading the country, with New Zealand First at $26, while the Greens are paying $34.

ACT ($67), the Maori Party ($126), the New Conservatives ($151) and The Opportunities Party ($151) aren't given much of a chance by the bookies at this stage.

While Labour are the front-runners, punters are picking that they'll need to form a coalition to remain in power. They're paying $3 to form a government by themselves, and $1.40 to need an ally such as the Greens or New Zealand First.

In terms of how many seats each party will win in Parliament, 56-60 are the shortest odds for Labour at $2.75. A massive win isn't off the cards, with a tally of 66-70 seats paying $7, while a brave bet on Labour getting more than 100 seats is paying $81.

The picture is less rosy for National, which is paying $8 to get 56-60 seats. The shortest odds for them are $2.10 to get 46-50, while the unlikely prospect of getting 100 or more seats is paying a whopping $151.

The Greens are paying $2.75 to get 7-10 seats and $3.25 to get none at all and ACT, the only other party on the seat totals, is paying $2.10 to get no seats and $1.50 to get 1-3.

Irish betting site Paddy Power is also taking bets on the New Zealand election, offering odds of 1/6 on Labour being the party of the Prime Minister, with National at 4/1, NZ First at 25/1 and the Greens at 33/1.

It's not yet clear how much of a change Judith Collins replacing Todd Muller as National leader will make on the party's election results.

A The Project-Yabble poll of 500 people found 60.8 percent of Kiwis prefer Jacinda Ardern stayed on as Prime Minister, while 22.6 percent were backing Collins.

A Roy Morgan political poll - the last released before Collins took over as leader - showed Labour had the support of 54.5 percent of those surveyed, with National getting less than half that on just 27 percent.