Winston Peters is set to become both Deputy Prime Minister and Foreign Affairs Minister when Jacinda Ardern signs Labour's coalition agreement with New Zealand First on Tuesday.
Mr Peters is believed to have locked down the roles during post-election negotiations, while his deputy Ron Mark is expected to take the reins as Defence Minister, according to Fairfax.
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It's not the first time Mr Peters has been in either of the roles - he was Jim Bolger's Deputy Prime Minister between 1996 and 1998, and Minister of Foreign Affairs in Helen Clark's Government between 2008 and 2008.
It is believed Mr Peters would also have taken the Foreign Affairs portfolio had he agreed to a coalition with National last week, rather than Labour.
The Green Party is anticipated to have nabbed three ministerial roles, but all of those will be outside of Cabinet, according to reports. Those roles are believed to be related to climate change and conservation.
The agreement Labour has with the Greens is expected to come into effect on Tuesday as well, with a separate ceremony organised to commemorate their deal.
NZME reports Labour's agreements with the respective parties means they will have 16 in Cabinet and five outside, while NZ First will have four inside Cabinet and one under-secretary and the Greens three outside Cabinet and one under-secretary.
After Labour's victory last week, former Prime Minister Helen Clark said she believed they would have little problem with New Zealand First, as long as they maintained communication.
"I think that actually a lot of the socio-economic approaches are not that different," she said.
"When Winston Peters and New Zealand First gave you their word, their word was their bond. We did not have any difficulty in the running of our Government [with them on board]."