Speaking to the Herald, Peters would not explicitly rule out Labour, but implied it would be very difficult to work with the party again.
"We were in government for three years. There were matters which were clearly not disclosed to me or my party - He Puapua and going to Ihumatao.
"Since the election you have seen the emergence of what are clearly race-based policies and a pathway to apartheid - there's no other word for it.
"They've ruled themselves out as far as we're concerned," Peters said of Labour.
He Puapua was not government policy, but a report commissioned by the Government on the ways to implement the UN Declaration on the Rights of Indigenous Peoples (UNDRIP), which the previous government had signed.
He compared possible talks with Labour leader Jacinda Ardern to talks held with former leader Helen Clark after the 2005 election.
"I had a meeting with Helen Clark in 2005 and said if you are going down that pathway then we will not even begin discussions."
Peters was particularly critical of UNDRIP.
"The UN declaration [on the Rights of Indigenous Peoples] came up when I was foreign minister and we did not sign up to it. We'd hardly got out of there when John Key was signing up to it."
He said NZ First "will not be working in Parliament with any party whose beliefs and policies threaten the fundamental principles of this country's democracy".
Peters believes co-governance is one such threat. Despite his strong words against Labour, Peters was careful to leave some wriggle room to work with the party in the future. He did not rule them out completely.
He said it was too early to tell what to think of National leader Christopher Luxon.
"I don't know about Christopher Luxon - I don't know what his position on these matters is. In the ensuing months we'll find out."
Peters said he would not make a decision on working with National this far out from an election.
NZ First was ejected from Parliament at the previous election, but polled 3 per cent in the most recent 1 News-Kantar poll, which was taken in early August.