The Companies Office has banned the directors of National Finance 2000 from acting as company directors for at least four years.
The company collapsed in May 2006, owing more than $25 million.
Trevor Allan Ludlow, Anthony David Banbrook and Carol Anne Braithwaite had been accused of mismanaging National Finance: by reckless trading, failing to comply with its prospectus, breaching directors' duties and failing to maintain adequate books.
Deputy registrar of Companies Peter Barker says they failed to understand their duties and responsibilities as directors, and let down investors.
Mr Ludlow and Ms Braithwaite are barred from acting as directors for four and a half years and Mr Banbrook for four years.
They face charges of making untrue statements in the prospectus and failing to comply with financial reporting standards.
The Serious Fraud Office is also investigating National Finance 2000.