The number of rental properties available in major New Zealand centres has dropped dramatically from last year, TradeMe says.

Head of Property Nigel Jeffries, told TVNZ 1's Breakfast today that the number of listings in Wellington has dropped by 69 per cent, and in Auckland by 35 per cent.

Nationwide, the number of rental listings has halved since the same time last year.

"We've seen shortages before but not to this level," Mr Jeffries said.

There are several reasons for the shortage, Mr Jeffries said, including a trend among renters to stay in their properties for longer, as buying a house is more difficult.