Winston Peters says New Zealand First could have got back into Parliament if the Serious Fraud Office (SFO) hadn't announced it would prosecute two people connected with the party just before the election.
A judge has found the defendants, who both have name suppression, not guilty of electoral fraud but one expert says the Electoral Act needs to be re-written.
The two defendants - who were not then New Zealand First MPs, candidates or board members - were found not guilty of fraudulently depositing money into a New Zealand First Foundation Account, in breach of the Electoral Act.
"It's an enormous relief," said Peters. "The reality was that there was a spurious claim made at the very beginning, backed up sadly by too many in the media who believe lies rather than the truth."
Peters, the NZ First leader, said the SFO's announcement six months before the 2020 election that it was laying charges shows there was something seriously rotten in the state of New Zealand.
One of the defence lawyers goes further.
"It has all the hallmarks of political interference in an election. New Zealand First did not return to Parliament," said Tudor Clee.
Asked if he thought he could have got back into Parliament, Peters said: "Well, of course, I do."
The pair were accused of obtaining nearly $750,000 by deception between 2015 and 2020 but Clee said they should never have been prosecuted.
"I think the information they were provided was by people who were disgruntled or who had a political axe to grind and unfortunately that was taken hook line and sinker."
The case turned on the judge's decision that donations to the New Zealand First Foundation were not donations to the party.
"If you had asked me or I think probably most other electoral lawyers before the hearing, was this a party donation, I would have been very clear it was," says lawyer Graeme Edgeler.
Edgeler was surprised by the decision and said the Electoral Act should be rewritten to ensure party donations get disclosed.
"If this interpretation is correct and now that a High Court judge has said it, we have to act on the assumption that the High Court Judge got it right, then yes.
Clee said the Electoral Act "may need looking at, but that doesn't mean that the SFO or anybody should be prosecuting a crime when a crime doesn't exist".
The SFO said there was real value in bringing this case and shining a light on the conduct in question.
Clee said it's possible there'll be further litigation on their side, especially since the prosecution said in court Peters could be viewed as "an uncharged co-conspirator".
Peters himself isn't ruling in or out further legal action.