The liquidators allege reckless trading and breach of director duties when they let the company trade with negative equity - when money owed exceeds the value of assets - from at least 2008. The directors vigorously deny any wrongdoing.
Shipley leaned forward and shook her head as BDO's lawyer O'Brien asserted that there was no reason to think the funding the company needed to continue trading would be forthcoming.
She was New Zealand's first woman PM leading the country from 1997-1999. Shipley still chairs Genesis Energy and China Construction Bank (NZ) and is on the board of food export company Oravida and the International Finance Forum in Beijing. She will retire from Genesis at the October annual meeting.
Liquidators Brian Mayo-Smith and Andrew Bethell of BDO hope the directors' professional liability insurance will allow them to recover up to $75 million for creditors, many of them unpaid subcontractors.
The addition of the insurance companies behind the case adds a certain frisson to the proceedings, as the case can be seen as a battle between litigation funder LPF Group, which is funding BDO, and the insurance companies standing behind the directors.
Bethell says the case is about more than just Mainzeal.
It's about the standards of governance and care owed by company directors in New Zealand towards the company and creditors.
"We say that when it became obvious that Mainzeal was insolvent, the directors had a duty to put strategies in place to enable the company to avoid substantial risk of serious loss from ongoing trading."