An agent negotiating to sell an elderly man's South Auckland home secretly accepted a $10,000 "finder's fee" from a potential buyer.
Gou (Nancy) Dai also divulged confidential information to the buyer about the owner's price expectation and the fact he was "very keen to get the property sold".
The private treaty sale was due to go ahead for $415,000 without her agency, Ray White Manurewa, ever being alerted.
The buyer even promised to give Dai the listing when the house was eventually on-sold.
The deal was only stopped when the Public Trust, which had an interest in the property through a family trust, stepped in to cancel the sale.
The property was sold two months later to another buyer for $540,000.
Dai voluntarily suspended her licence once her offending came to light and later pleaded guilty to three misconduct charges.
She told the Herald the last two years had been "hell" and she had no intention of returning to the industry.
"It's hard work and you don't really get reward. Anyone can penalise you and anyone can sue you."
The Real Estate Agents Disciplinary Tribunal heard that the owner contacted Dai about selling his Manurewa home on May 8, 2015.
She discussed marketing plans with the owner and he told her he wanted $420,000 before decided not to list it with Ray White.
Dai then revealed she could facilitate a "private sale". She contacted a potential buyer, named as "Mr Honey" in the summary of facts, telling him the owner was "very keen" to sell and divulging his desired price before introducing the two men.
"Mr Honey signed a handwritten letter agreeing to pay the defendant $10,000 as a 'finder's fee' and that he would give the defendant the listing for the property after he renovated it."
A sale and purchase agreement was eventually signed for $415,000.
Dai did not disclose her involvement to her employer or reveal the $10,000 finder's fee agreement.
The Public Trust became involved soon after and refused to endorse the deal.
Ray White head of agency operations Graeme Fraser said: "Ray White agree with the REAA findings and accordingly Ms Dai has not been engaged since 2015."
Dai told the Herald: "I thought I would help the buyer, help the vendor. I just introduced them. They did the deal themselves."
She said she did not receive the finder's fee payment and refused to comment further when pressed about her actions.
Prosecutor Kate Lawson-Bradshaw argued Dai's actions were deliberate and "involved an element of dishonesty".
Her disclosure of confidential pricing information was a clear conflict of interest "and the penalty should include an element of deterrence".
The tribunal suspended Dai's licence for six months, labelling her offending a serious breach of the Real Estate Agents Act.
A Public Trust spokeswoman said it hoped the investigation and subsequent disciplinary process would serve as a reminder to others agents that such activity was unacceptable.
The trust's standard approach was to obtain two real estate agents appraisals and a registered valuation before putting a property on the market.
An REAA spokesman said it maintained an "active watch" for agents working in cahoots with buyers.
A small number of agents did not adhere to ethical standards but would be brought before the formal disciplinary process when offending was exposed.