Mr Stewart, the sole director of Stewart and Associates, was the principal of the firm and solely responsible for managing its trust account.
The tribunal's decision said Mr Stewart pleaded guilty to two charges and voluntarily stepped down from practice before the hearing, held on September 6.
He was ''fully co-operative from the inspection stage and throughout the disciplinary process'' and had taken responsibility for his actions, the tribunal decision said.
Mr Stewart had been a lawyer for 32 years and had an unblemished disciplinary record before these matters.
He practised on his own, and had had a trust account since February 2009. Irregularities in the trust account's record-keeping were noted during a routine inspection by the New Zealand Law Society.
These included a failure to keep adequate records, client balances overdrawn, failure to reconcile bank accounts with the trust ledger and incorrectly certifying compliance with the Act and regulations.
The irregularities extended over three years.
Mr Stewart corrected all the errors found by the inspector and there were no remaining concerns by the time of the inspector's third visit, the tribunal said.
Mr Stewart had admitted the charge of negligence in his professional capacity of such a degree to reflect on his fitness to practise or to bring his profession into disrepute.
The tribunal said this was its first decision on a breach of the rule that prevented a lawyer operating a business which provided other services to a client unconnected with regulated services.
In this case the business provided banking services.
Mr Stewart admitted the charge of misconduct by providing banking services.
The tribunal said this charge was serious because of the privileged nature of a lawyer's trust account.
Mr Stewart became a director of a company which assisted overseas people wanting to migrate to New Zealand. The company promoted his law firm as a provider of banking services through his lawyer's trust account, the decision said.
Mr Stewart was ordered to pay the Law Society $16,000 and to reimburse the hearing costs of $2488.
Stewart and Associates' website said the firm was established in 2010 and offered a full range of legal and realty services.
Mr Stewart could not be reached for comment yesterday.
