Nguy was also charged with obstructing the Auckland Standards Committee for which he was found guilty of misconduct.
He was censured by the tribunal and ordered to pay costs, Stuff reported.
Nguy had been suspended from practice until the disciplinary action being taken against him concluded, according to the NZ Law Society.
The Auckland Standards Committee No 2 made the suspension application after Nguy's apparent misapplication of more than $1.3 million, which was related to a property purchase of a client.
The property's vendor made several attempts to settle with Nguy, according to the Law Society, and took legal action against his client when this failed.
The tribunal said of Nguy's behaviour: "It is a fundamental obligation on solicitors to be scrupulous in dealing with client funds. Mr Nguy's conduct in this case has shown repeated breaches covered by associated dishonest representations. We are readily satisfied that it is in the interests of the public to suspend Mr Nguy from practice until the charges against him have been disposed of".