A Bayleys spokesman said the companty was appealing against the decision on a matter of interpretation.
The buyers laid a complaint last year after receiving a body corporate letter in July 2010 seeking approval to spend $7500 to repair the apartment above their own.
A subsequent inspection of their apartment found major defects that were not discovered in a pre-purchase inspection, and significant repairs were needed.
Before buying the apartment, the complainants said they had on a number of occasions asked whether there were any leakiness issues, but were assured there were none.
The buyers also complained they were pressured into the sale by signing a multi-offer form, which made them believe there were other offers on the apartment when there were not.
The authority found Ms Peacocke did not go far enough to advise the buyers the apartment was potentially leaky, given its age and construction from monolithic cladding.
It also found undue pressure was put on the buyers with the multi-offer form.
Ms Peacocke argued that was standard company policy for a sale that followed an unsuccessful auction, but the authority found she shared some responsibility.
It also found that policy was unethical and ordered Bayleys North Shore to stop the practice.
As mitigating factors, the authority noted the vendors had withheld information about the apartment's potential leakiness from Ms Peacocke.
It also found the buyers were not diligent enough in their research and preparation ahead of buying the property.
The complainants sought more than $100,000 in repair costs, damages of $25,000 and reimbursement of almost $4000 in legal fees.
The authority said it was unable to order compensation or damages, and did not believe legal costs should be reimbursed.
The maximum fines it can impose are $10,000 for individuals and $20,000 for companies.
