John Banks is seeking to have a second trial for filing a false electoral return thrown out after the discovery of evidence which the Crown failed to disclose to his QC.
The parliamentary career of the former Act leader ended after he was convicted in the High Court last year for not disclosing two $25,000 donations from internet mogul Kim Dotcom to his Auckland mayoralty campaign in 2010.
The Court of Appeal then quashed the conviction after the "obsessed" detective work of Mr Banks' wife, Amanda, who was stung by the trial judge's opinion of her credibility when he preferred Mona Dotcom's evidence about a lunch which was crucial to the case.
Mrs Banks tracked down two witnesses from America who corroborated her version of events and whose evidence the three appellate justices said was "likely to have changed the outcome of the trial", if accepted.
A retrial was set for July but Mr Banks' lawyer, David Jones, QC, is now seeking to have the charge dismissed after receiving a document which he said "contradicts all the evidence given at trial" by the Dotcom witnesses and makes the Crown case "untenable".
Last week, he received fresh material from the Crown about the contentious lunch at the Dotcom mansion which has been released to the Weekend Herald by the High Court.
The memorandum was written by lawyer Rowan Butler who was instructed by crown prosecutor Paul Dacre, QC, to interview Kim Dotcom about the affidavits filed by the two American businessmen before the Court of Appeal hearing.
The pair said they arrived in New Zealand on June 5, 2010 and were taken to Dotcom's Coatesville mansion, where they had lunch with Mr and Mrs Banks and Dotcom and his wife Mona. Nothing about electoral donations was discussed, according to their affidavits.
This is at odds with evidence given at the trial, where the Crown contended the lunch was held on June 9, 2010 and the presence of the Americans was denied by the Dotcoms, as well as their bodyguard Wayne Tempero.
The defence was able to prove at the trial there was no lunch on June 9, because Mr Banks was campaigning and Mrs Banks was at work.
In finding Mr Banks guilty, Justice Edwin Wylie said Dotcom was a good witness but he was wrong about the date of the lunch and ruled it must have happened on June 5.
But when interviewed by Mr Butler about the new affidavits before the Court of Appeal hearing, Dotcom accepted the evidence of the US businessmen - including that donations were not discussed at the June 5 lunch. Instead, he said there was a second lunch - again on June 9 - at which the donations were discussed.
The interview with Dotcom was never disclosed to Banks' legal team before the Court of Appeal hearing.
His lawyer has filed a memorandum to the High Court seeking a hearing to have the charge against Mr Banks dismissed for lack of evidence.
The newly disclosed material contradicts all the evidence given at trial by the Dotcom witnesses, wrote Mr Jones.
"It has never been part of the crown case nor has there been any prior suggestion that there were two lunches within a matter of days of each other, at which both Mr and Mrs Banks were present," wrote Mr Jones.
"How the Crown can now properly pursue this prosecution in the circumstances is unknown ... the crown case will accordingly have to be completely recast in a way which, with respect, is utterly untenable."
Mr Jones was also critical of the late disclosure of the Butler memorandum. "If this material had been before the Court of Appeal, which it should have been, it is submitted it would have been a critical factor not only on the substantive appeal but also in the decision whether to order a retrial or not.
"It is the defence position that the continuation of this prosecution is an abject abuse of process.
"The defence brings these matters to the attention of the court given the serious nature of them and the inevitable impact they will have on the progress of this case."
In response, crown prosecutor Paul Dacre, QC, wrote that new witness statements from those who were at the lunch were now being sought.
Once this was completed, Mr Dacre said, the alleged date of the lunch would be provided and full disclosure would be made "when the materials come to hand".
He also consented to a hearing date being fixed for Mr Jones' application for the charge to be dismissed.
The case will be discussed further at a teleconference on Monday.
The story so far
• April 2012 - Kim Dotcom's $50,000 of anonymous donations to John Banks' mayoral campaign in 2010 become public.
• July 2012 - Police do not lay charges after investigation.
• November 2012 - Graham McCready takes private prosecution against the Act MP.
• October 2013 - Banks resigns as a Minister after Judge Phil Gittos rules he should stand trial.
• June 2014 - Banks found guilty after a High Court trial. Later he resigns from Parliament.
• November 2014 - Banks is successful in overturning the conviction in the Court of Appeal.
• January 2015 - Solicitor-General Mike Heron, QC, confirms a new trial. Scheduled for July.
• March 2015 - Banks' lawyer David Jones, QC, seeks to have charge dismissed after the late disclosure of new material from the Crown.