Prime Minister elect John Key has announced the formation of a National-led centre-right government supported by Act.
At a joint press conference with Act leader Rodney Hide today, Mr Key announced he had formally signed up Act's support.
The Maori Party also confirmed today it will sign a deal with National and Mr Key is scheduled to announce a similar deal with United Future later today.
"National and Act have many areas of common interest and both parties have shared goals, including wanting to see a more prosperous and cohesive country driven by initiative and hard work," Mr Key said today.
"There is a recognition from both sides that in order to promote strong growth in investment, employment and incomes, stable government and high levels of business confidence are required."
Act's deal includes ministerial roles outside Cabinet for Mr Hide and deputy Heather Roy and policy concessions.
Policy concessions included an advisory group to look at ways of closing the income gap with Australia by 2025 and task forces to review government spending.
Under the deal Mr Hide will be appointed Minister for Local Government, Minister for Regulatory Reform and associate Minister of Commerce. Mrs Roy will be Minister of Consumer Affairs and associate Minister of Defence and Education.
"Act has agreed to support the legislation required to implement National's election promises outlined in the Post-Election Action Plan and the My key commitments to you card," Mr Key said.
"I welcome Act's support to establish a National-led government. We look forward to working in a constructive way to advance the interests of New Zealand, for all New Zealanders."
Act won five seats on election night and along with United Future, which won one, pledged to support National, meaning National's haul of 59 seats assured it a majority in the incoming 122-member Parliament.
But Mr Key's success in signing up the Maori Party means National could command 70 votes on confidence and supply issues.
Mr Key's formal inking of the deals paves the way for him to announce his Cabinet tomorrow and for him and his ministers to be sworn in on Wednesday.
That will allow Mr Key to fly out on Thursday to the Apec summit in Peru at the weekend as New Zealand's new Prime Minister.
United Future leader, and the party's sole MP, Peter Dunne concluded negotiations with National last week, saying a deal had been agreed and was waiting to be signed.
The Maori Party also said last week it had completed a draft agreement with National, but wanted to consult its supporters at a series of hui before it signed a deal.
Mr Dunne and Maori Party co-leaders Pita Sharples and Tariana Turia are also expected to be given ministerial positions outside of Cabinet.