Watch: Enemies to frenemies – take a look back at Winston Peters' savage comments about his new colleagues

A lot can change in the space of a few weeks - especially in politics.

Winston Peters last night announced a Labour-NZ First government, which will be supported by the Greens, and with Labour leader Jacinda Ardern as Prime Minister.

This comes just weeks after the three parties were at loggerheads with each other, trading blows on policies such as water tax and immigration.

Before negotiations and last night's announcement, the Labour Party had promised to clean up New Zealand's rivers by introducing a water tax which NZ First strongly opposed.

"You're between the devil and the deep blue sea with this policy and we're opposing both you on this matter," Mr Peters told media in the lead up to the election.

Ms Ardern responded by saying: "I have a firm commitment to cleaning up New Zealand's rivers and I hope anyone who forms a coalition with us would have that firm commitment too."

There were back and forth comments from Labour and NZ First over Labour's tax policy and stance on child poverty.

There was also a lot of finger pointing when it came to former Green Party co-leader Metiria Turei's benefit scandal and Mr Peters' superannuation overpayment.

No party butted heads during the election campaign more than the Green and NZ First Party with Ms Turei calling Mr Peters' immigration policy "racist".

Mr Peters fired back at those comments calling the Green Party an "albatross around Labour's neck".

He went on further to say New Zealanders don't won't to be run by the "ragging lunatic" Green Party.

After nearly two weeks of negotiations, Mr Peters announced his decision today. Source: 1 NEWS

Now after two weeks of negotiations the three parties seem to have put these differences aside to put National into opposition.

It wasn’t all smiles and compliments for Labour, NZ First and the Greens during the election campaign. Source: 1 NEWS