As the leaders handle the top-level talks there are reports of intense behind-the-scenes activity to thrash out policy agreements.
National and Labour have been preparing for the talks since the election, and they've both done the groundwork on the differences and similarities of their policies when they're put up against NZ First's.
Mr Peters is believed to have an extensive list of NZ First policies he wants implemented, ranging from immigration cuts and regional development to enhanced SuperGold Card entitlements.
The meetings are taking place in a neutral venue at Parliament, and security around them is being tightened.
All three teams have agreed the negotiations will be strictly confidential.
Mr Peters wouldn't begin formal negotiations until final election results had been announced. They came out on Saturday, confirming that neither National nor a Labour/Greens alliance could command a parliamentary majority without NZ First.