The number of listings is down 7 per cent across the country, with bigger decreases in Wellington (12 percent) and Hamilton (9 percent).
Supply remains strong in student centres Dunedin (up 17 percent) and Palmerston North (up 13 percent).
The decrease in listings coincides with an average rent increase of 4 percent across New Zealand and 7 percent in Auckland.
Mr Skipper said although more listings were coming onto Trade Me Property, they were "not sticking around'' for long.
"So far this year, about a quarter of all listings in Auckland, Wellington and Christchurch were onsite for six days or less, which is great for landlords but another indicator of that strong tenant demand.''
He said there were signs pressure in the rental market was pushing prospective tenants to consider buying a house.
"Looking at our property for sale activity, we can see demand from potential buyers has increased by 13 per cent over the quarter, while sales inventory remains flat.''