The Mainzeal directors found liable for reckless trading are challenging the procedural nature of their trial as they appeal a $36 million judgment against them.
Former Prime Minister Jenny Shipley, Peter Gomm, Clive Tilby and Richard Yan are appealing Justice Francis Cooke's finding that they had breached directors' duties ahead of the construction company's 2013 collapse.
On day two of the five-day Court of Appeal hearing, the lawyer for Shipley, Gomm and Tilby, Jack Hodder QC, launched an attack claiming procedural "unfairness".
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It is not clear whether, if the directors win on this point, a retrial would be needed with the recalling of witnesses such as Shipley, Yan or parent company Richina Pacific's John Walker.
The directors say that a pivot in the way the case was argued, suggested by the judge, began on the 26th day of the 41-day trial, and that this was unfair to them.
"We came to court on the Tuesday, it was after Labour weekend, and his honour said essentially ... 'I've been thinking,'" Hodder said.
Hodder then went on to recount how Justice Cooke said there was a "mismatch" in the case unfolding and the case pleaded, and that it was "something that has been troubling me".
The judge decided that he could consider the quantum of loss on a different basis than the liquidator did and asked the defendants to call further evidence on that if they wished.
The change was made after the liquidator had completed presenting his case and Shipley and Yan had finished giving evidence. Yan is being represented separately and his lawyer has not presented his arguments.
The directors now say this pivot constituted "irremediable unfairness" since they had spent three years preparing their defence to the case made by the liquidator.
They say they couldn't produce further evidence at the time but have since filed an affidavit by KordaMentha's Grant Graham in support.
Justice Forrie Miller asked why this complaint had not been made when Justice Cooke invited further submissions on quantum, which was dealt with in a separate judgment later in 2019.
Hodder's response was that the defence had filed its notice of appeal by then.
"So your furious complaints were directed a few hundred metres up the road," Justice Goddard noted.
Whether her role as board chairwoman meant Shipley should be liable for more of the claim was also the subject of debate today.
Mainzeal's liquidator said the former prime minister should shoulder more of the liability because of her role as chair. At the trial stage Shipley, Tilby and Gomm were held liable for $6m each, with $18m awarded against Yan.
Shipley's lawyer Michael Arthur told the Court of Appeal that while he acknowledged there was precedent for chairpeople being held more liable, that was for listed companies and Mainzeal was not listed at the relevant time.
He added that where chairpeople had been liable for more was in cases of dishonesty or misrepresentation, not where there were honest directors as in this case.
The directors say that $6m for each non-shareholder director is "plainly a crippling amount for any New Zealander not possessed of extraordinary wealth," and that the court should lower the figure, if it upholds the claim.
The proceeding continues.