An advertising campaign which appeared to celebrate making tenants life a misery was mailed out to more than 1600 Wellington homes.
The now deleted advertisments featured beer glasses with the caption "Cheers to you! Are you financing your tenant's social life?"
A second claims that "Your tenants may hate us. You will love us," While a third says 'Afraid to man up? We aren't.'
Quinovic initally claimed the advertisements, which were organised by their Te Aro franchise, only appeared on Facebook.
But listeners contacted RNZ to say they received the personally addressed advertising cards in the mail.
Quinovic now admits 1650 of the cards were sent to Wellington addresses, organised through a mail-out company.
It declined to comment further.
Tenants were quick to express their outrage on social media yesterday, and now landlords have jumped in.
A landlord and president of the Wellington Property Investors Association, Richard Bacon, said he was horrified by the ads.
"I was disgusted...and all of the comments I've seen from other landlords on Facebook have been disgusted," he said.
"It's been ill-advised and un-professional, and just not the way landlording works in New Zealand."
Mr Bacon said the ads were uninformed and wrongly suggested that landlords would enjoy using a property manager who treated tenants badly.
"I have no real idea why they are doing it and Quinovic, as a group, is now distancing itself from the adverts, it's now obvious that they didn't do any research before they put the adverts together."
Real Estate Institute New Zealand (REINZ) chief executive Bindi Norwell said the ads showed industry needed regulation.
"It's disappointing to hear an example of property managers not living up to expectations on how property managers should act," she said.
"I think stories such as these really highlight why REINZ has been calling for property managers to be regulated so there is consistency and transparency across the market of what is appropriate and what's not."
Quinovic Te Aro has deleted the ads and has issued a formal apology to anyone it may have offended.