The Law Society said that the tribunal found that Banbrook, who did not appear at a hearing held last month "acted in clear disregard of the order suspending him from practice as a barrister and attempted to conceal the true nature of the legal work he was undertaking".
New Zealand Law Society President Kathryn Beck said Banbrook's behaviour illustrated a serious neglect of the standards of professionalism required from a lawyer.
"Practising law while under a suspension order shows he made a conscious decision not to comply with it. He showed a reckless disregard for the disciplinary process and the only available conclusion is a strike off to uphold the reputation and standards of the legal profession," she said.
Banbrook was ordered to pay $10,000 to the complainant and $56,349 in costs to the Law Society and to refund $3516 in costs to the society.