Some agents claim it can sometimes be because, as markets recover, sales prices are being compared with properties sold for much less during the recent downturn.

In Sydney’s Mosman, the median house price is $3.6 million. Sam Mooy

In Mosman, Richard Simeon, principal of Simeon Manners, which is based in Sydney’s Mosman, where the median house price is $3.6 million, is concerned advertised prices listed on the internet immediately after sale are sometimes higher than the sale price.

This can happen because it can take up to 16 weeks between an exchange of contracts and the settlement of sale.

For example, a five-bedroom, six-bathroom house in Burran Avenue, Mosman, advertised as selling for $15 million on July 29 was later revealed to have sold for $11.2 million.

Mr Simeon, who has sold two of the four properties which have gone for more than $10 million this year, said: “I know of many vendors and buyers who relied on this reported sale of $15 million to apply the values to their own property, or what they should pay for comparable properties.”

Other agents also claimed the $3.8 million difference caused a lot of comment and confusion because it was much higher than other recent sales in the area.


The advertisement was removed following complaints from local agents.

Jonathan DeBrennan, principal of DeBrennan Property, which sold the property, said the sale price was withheld and denies his company leaked any information to the market. Mr DeBrennan said he was unaware of any advertisement that included the $15 million sale price.

"We have not stated the sale price," he said. "The $15 million figure did not come from us." He said he was not aware of where the information could have come from.

David Murphy, principal of David Murphy Residential, said accurate sale prices should be available when contracts are exchanged and that there should be penalties for providing inaccurate or misleading information.

Mr Murphy said underquoting was increasing as markets improved.

Mr Morrell claimed regulatory attempts to police and punish offenders, which included "flying squads" that investigate alleged breaches, are like a “slap in the face with a wet lettuce for the offender”.

State governments have different policies intended to prevent underquoting.

In Victoria, agents must provide a quote and are expected, where possible, to support it with prices from recently sold comparable properties.

Hoskins Real Estate Croydon and director Brent Peters was recently ordered to pay penalties and compensation totalling $889,550 for underquoting 24 properties.