"We're sorry if anyone got confused about this one," TradeMe communications and community spokesman Jeff Hunkin said.
He said the false listings were believed to be from an old file with information from January, but it was not clear exactly how it happened.
"From our point of view, as soon as we noticed something was wrong we got onto fixing it."
Mr Hunkin said "there was no sensitive data involved as these appeared onsite as classified ads, but it would have been annoying for members searching for listings and attempting to contact the agents via the incorrect contact info".
The couple that spent more than two hours looking through the listings said they were further frustrated after finding a home they were interested in.
"We were amazed at the number of new listings and we stumbled across the perfect place in west Auckland," they said.
"It was just what we'd been looking for, in the right area and in our price range. I texted the agent but never heard back. We tried to contact her again but found the number was no longer working and the 'expired' ad had been taken down."
They said they were "hugely disappointed" and "angry" at having wasted two hours because of a fault in the system.
Mr Hunkin said there had been no official complaints about the wrongful listings.
"We do encounter occasional problems with the property listings feed, but we fix them as soon as we're made aware of the issues," he said.
"If people do see something out of the ordinary we'd encourage them to get in touch by using the community watch button or by contacting us. We have policing and customer service teams here 24/7."
He said there were more than 100,000 properties listed for sale on TradeMe.
