Whisky for Winston Peters as James Shaw greets new coalition partner for first time

Green Party leader James Shaw has given Winston Peters a bottle of whisky as a sign of good faith ahead of governing together for the next three years.

Shaw told Rachel Smalley on Newstalk ZB's Early Edition that the pair officially met for the first time last night after the Supply and Confidence agreements had been signed.

"It was sort of the first moment that either of us had, really, to catch our breaths so we had a quick catch-up in my office."

He described the face-to-face meeting as "good". The pair talked about the two parties governing in coalition for the first time.

"It was a social call rather than a business call," Shaw told Smalley.

The pair didn't share a whisky - Peters' favourite tipple - but Shaw surprised the New Zealand First leader with a celebratory bottle.

"A bottle of whisky was exchanged in good faith from me to him," he said.

Shaw also said the Green Party made the choice for its three ministers to sit outside Cabinet for the next three years.

"We had a range of options in front of us, which we had spent some weeks thrashing out. They ranged anywhere from sitting on the cross benches right through to being in Cabinet and at every step of the process - and I think this is because of the relationship that we've built up with Labour under the Memorandum of Understanding that we had with them - Jacinda was very clear at every step of the way it was our choice." Despite the key climate change portfolio - dubbed by Prime Minister-elect Ardern during the election as the nuclear-free issue of her generation - sitting outside Cabinet, Shaw said in practical terms it would not make a huge difference as ministers would sit on committees to thrash out details.

He acknowledged the relationship between the two parties had been strained at times over the years but there had been a good level of collegiality between politicians while in Opposition.

"We've never had a close working relationship and we now are."

Shaw said a confidentiality arrangement governed negotiations, and the Labour Party only agreed to Green policies they knew New Zealand First could accommodate.

He said that would reflect how the coming three years would work. Shaw today said the biggest policy gain for the Greens during coalition negotiations was a commitment to a net zero emissions economy by 2050.

"Ultimately what that means is a substantial re-gearing of the whole economy and I believe what that means is higher productivity, higher wages, more jobs and so on."