NZ First will meet with the National Party before meeting with Labour for discussions on forming the next Government.
NZ First leader Winston Peters said in a statement preliminary discussions will begin with National in the morning, before a meeting with the Labour Party in the afternoon.
Labour leader Jacinda Ardern told Newshub on Wednesday afternoon "one meeting has to happen before the other."
"The importance, of course, is meetings are being had and we are preparing to form a stable durable Government."
On Monday, Mr Peters indicated preliminary talks would begin with both parties this week. He had previously said talks would begin once special votes are in on October 7.
Mr Peters has said a decision will be made by October 12, when results are presented to the Governor-General.
National leader Bill English is less confident about the time-span, telling Newshub "it's quite a complicated process" and National has never managed it within four or five days.
Ms Ardern said it would be "absolutely possible" to meet Mr Peters' timeline, with preliminary talks meaning the parties could move swiftly once special votes are counted.
"We are being ambitious around trying to work through the issues as quickly as we can."