"We're usually pretty quick at getting it down but we strongly urge any users with concerns to get in touch with us so we can check it out from our end before they make contacts through the ad," Duffy said.
Most scam listings came as a result of phishing where users inadvertently gave their log-in details to scammers, thinking they were dealing with a legitimate site, he said.
Last Tuesday was Safer Internet Day, an international drive for shared responsibility, he said.
Internal Affairs said phishing emails pretend to come from a financial institution such as a bank and urge you to click a link to the company's website and enter your bank account details, credit card information, password, passport information, home address, or even your IRD number. Many websites are clever fakes, and typing in your details could result in your bank account being emptied by fraudsters, it warns.
Barfoot & Thompson director Kiri Barfoot issued a plea for publicity in an attempt to stop prospective tenants losing money after she found her company's ads had been copied.
Barfoot was aware of three cases where would-be tenants had fallen for the scam: two in Royal Oak and one in Mt Albert.
But she said she knew of only one tenant who had paid money in the scam, losing about $2000 deposit and rent in advance on an Auckland place.
Detective Inspector Scott Beard, Auckland City District's field crime manager, said last week that no formal complaints had been made over property in Auckland.
"Our Financial Crime Unit has been contacted by some people who have discussed the issue, but we have not received any official complaints," Beard said.
He warned people to be wary but said there was little to be done.
"This is all online and money goes overseas. Police prevention advice is that people need to check the bona fides of anyone seeking money from them."
Helen O'Sullivan, REINZ chief executive until the end of last week, also warned people to be wary.
Tenant Debbie Kebbell said she was looking for a place in Wellington when she found a flat on Wellington's Lambton Quay which looked exceptional value at only $150 a week.
The owner claimed to be deaf and living overseas and told Kebbell she couldn't see inside but asked for more than $1000 deposit and rent so the keys could be sent.
Her mother, Jocelyn Kebbell, helped her escape that scam.
"It just didn't seem right. Their emails didn't make sense. I might have fallen for it if I hadn't told my mum," she said.
In Auckland, Rajeev Puri had an email from Pastor Fred Jones in West Africa telling him a Mt Albert house was available for $450 a week and he should pay bond of $1350 and a week's rent to get the keys.
