He laid the blame for the opposition's defeat at Labour and the Greens' door.
ELECTION INTERACTIVE: Every vote, every seat, every result
"Labour and the Greens grossly let down everybody in this campaign," he said.
"What was planned in this campaign by the Greens for example was pretty terrible in the form of their attack on the Labour Party in the middle of the campaign ... and in the end you cannot have that kind of internecine strife going on both in the Labour Party and in the Greens against the Labour Party and hope to win."
He also criticised Labour for moving away from its roots representing working people and instead getting side-tracked by in-fighting among MPs that "want to push their own narrow issues".
National's campaign director: Deal with NZ First 'highly unlikely'
"They need to take a good hard look at themselves."
Mr Peters said NZ First, which he claimed was "seriously marginalised" by the media during the campaign, was "never part of that group any more than we were part of the other group".
Mr Peters all but ruled out any deal with National in coming days. "Why would John Key call me when he doesn't need the numbers unless he wanted to keep my mouth shut about things that I know have gone on in this country," he said.
"We are not going to be bought out by anybody."
Instead, NZ First would be the "leading opposition party".
"We've got the experience and the record very much of both transparency in terms of keeping the system honest than anyone else."
Last night's result left the party "very strong, no doubt about it", he said.
Mr Peters warned the Prime Minister that within a few months "people will see with great clarity what we meant when we said this country is not a rock star economy, it is seriously in trouble, that's why Mr Key called the election early".
He also told TVNZ's Q+A that the issues raised by surveillance whistleblowers Edward Snowden and Glenn Greenwald would continue to dog Mr Key.
However, he was also pleased to have had some hand in ensuring Kim Dotcom's bid for political influence was stymied by Mana Party Leader Hone Harawira's defeat in the Tai Tokerau electorate at the hands of Labour's Kelvin Davis who Mr Peters endorsed in the final days of the campaign.
Mr Peters also took clear pleasure from Colin Craig's Conservative's failure to top the 5 per cent threshold and make it into Parliament. "There's been some great positive things out of this election and I'm glad I'm part of them."
App users: Tap here for 'Craig Conservative Party Highlights'
Among the new NZ First MPs, are Fletcher Tabuteau the party's Rotorua candidate and a manager and lecturer in economics and marketing at Waiariki Institute of Technology who leapfrogged sitting MPs into fourth place on the list.
Clayton Mitchell at no. 6 on the list is currently a Tauranga City councillor, a surf lifesaver and a judo coach.
Last night's result also sees the return of two former NZ First MPs, Waitangi Trust chairman Pita Paraone and Carterton Mayor Ron Mark.
The fifth new face is Darroch Ball, a Palmerston North based teacher and former army officer while the Mumbai born and raised Mr Bindra was NZ First's Mt Roskill candidate.
