Former Prime Minister Jenny Shipley and husband in High Court for opening day of Mainzeal case

The building company's former directors, including Shipley, Paul Collins and Richard Yan, are accused by the company's liquidators of reckless trading and breaching director duties when they let the company trade with negative equity.

Mainzeal collapsed in early 2013 owing more than 115 million dollars to unsecured creditors.

Lawyers for the liquidators BDO today argued Mainzeal was "dangling by a thread" and directors should have understood the risk.

They hope the directors' professional liability insurance will allow them to recover up to 75 million for creditors, many of them unpaid subcontractors.