Hart, 71, was earlier found guilty by a Lawyers and Conveyancers Disciplinary Tribunal of professional misconduct when he "grossly overcharged" clients for his services.
The Law Society asked the tribunal to strike him off - a move described as the "ultimate sanction" by both prosecution and defence at the tribunal hearing.
Hart had charged a client's family $1000 an hour, despite much of the preparation work being done by a junior lawyer who had been practising for only two months. On one occasion, fees charged for "waiting time in court" totalled $35,000, $20,000 more than a Queen's Counsel said they should have been.
Mr Hart agreed to repay $20,000 to a client the tribunal found he overcharged and the Law Society sought prosecution costs of more than $116,000. The tribunal costs were around $42,000.
The New Zealand Law Society said the decision to strike Hart from the roll of barristers and solicitors showed that conduct that impeded the effective regulation of the legal profession was viewed extremely seriously.
Law Society President Jonathan Temm said New Zealand's 11,500 lawyers were required to meet very high standards in the way they acted with their clients, with other lawyers, and with the Law Society which regulates the profession.
"Striking off is a severe penalty. It obviously has serious consequences for the lawyer who is struck off. However, as the legislation, the tribunal and our courts have stressed, the main purpose of striking off is to protect the community and maintain the standards of the legal profession.
"All lawyers have a duty to co-operate with and assist in regulating the profession. The tribunal's decision has shown that New Zealanders can have confidence that there is a clear process which ensures that obstruction of professional regulation is not acceptable," Mr Temm said.
Mr Temm said the tribunal had stressed that a lawyer's approach to the Law Society's investigation was a crucial factor and was particularly critical of what it described as "the arrogant and derisory manner" in which Mr Hart had approached any complaint of his conduct.
