He said Mr Key was now trying to lure him into supporting the Resource Management Act reforms by claiming it was holding Northland back. "That's diabolical humbug."
National had talked up the stability of its Government, so should not now try to lay the blame on him if it could not pass the RMA reforms. "It should go across to the parties that they own in every respect."
Mr Peters' win has meant National can no longer rely on only Act to pass legislation, giving increased influence to United Future's Peter Dunne and the Maori Party.
However, Mr Peters said he had no intention of letting those parties flex their muscle. "I've made it very clear that we didn't slog it out up north to have them in any way think they are going to be the beneficiaries of it. No way will Peter Dunne, the Act Party or Maori Party be allowed to behave in this way."
He would not reveal how he would stop it, but said it did not mean he would sweep in on his white steed to support legislation so National didn't have to go to Mr Dunne or the Maori Party.
NZ First was willing to talk to any other parties over "reasonable measures" and had worked with National over the GCSB legislation, though ultimately did not support it.
Mr Peters returns to Parliament today after a month of campaigning.
After earlier raising the possibility he would not resign his list seat to take in an extra MP, Mr Peters has now confirmed he will resign.
He was getting legal advice on whether that should be before or after final results were confirmed on April 8 and he was sworn in as Northland MP. If he resigned before then there could be a short period in which he was not in Parliament and NZ First numbers were down to 10.
NZ First President Anne Martin said the board would meet after final results to discuss issues including who would take up the next list slot. Parliamentary staffer Ria Bond is next on the list but if she says she is not available for the role, it would go to Mataroa Paroro.
The board cannot decline on her behalf but could ask her to decline it if they felt someone else was better suited to it. It is understood there is no objection to Ms Bond taking the seat, although nobody in NZ First would confirm that. Mr Peters said it was a board matter and although he was on the board he did not want to circumvent the process.