The owner of collapsed New Zealand broker Herbert Insurance Group has been found guilty of corruption.

Between 2005 and 2011 Grant Herbert received premiums from clients but did not forward about $NZ2.5 million ($2.25 million) of them to insurers, in some cases leaving the customers uninsured, according to the Serious Fraud Office (SFO).

The money went to pay the company’s operating expenses.

Last week the 62-year-old was convicted at Auckland District Court of 17 charges under the Crimes Act relating to theft by a person in a special relationship and seven charges under the Secret Commissions Act.

Herbert Insurance collapsed in March 2011 with a shortfall owed to insurers.

The corruption offences were uncovered during an SFO investigation into the collapse. They related to a deal between Herbert and former Bunnings commercial property manager Christopher David Green.

Herbert paid Green to place business through Herbert Insurance.

Green, who was sentenced last year, received $NZ220,000 ($197,739) in secret commissions, which he shared with Herbert, and Bunnings was overcharged that amount.

Herbert had pleaded not guilty to all the charges.

Before the trial he pleaded guilty to using a forged document to obtain a $NZ250,000 ($224,703) credit facility.

Herbert was remanded on bail and will be sentenced on October 16.

SFO Director Julie Read says Herbert breached the confidence of insurers and clients and exposed clients to significant losses.

“The offending [that] Mr Herbert engaged in undermines the insurance broking industry and the insurance industry itself, which is largely based on trust,” she said.

Herbert Insurance had about 4000 clients. Aon bought the book from the receiver and mounted an industry rescue to ensure clients were covered.