"We've also seen appreciation in land values over the last year… we've also seen a shortage in rentals so we've got three factors that come into play."
Anderson said it was getting harder for land owners to look after their rentals as compliance costs and requirements rose.
This included the healthy homes bill and rules around heating and insulation.
As a result, Anderson said, more landlords were thinking of selling which created more of a shortage.
Nationwide the median rent rose 4.4 per cent to a high of $470 per week.
Head of Trade Me Property Nigel Jeffries said renters had to be quick.
"Tenants are having to get in quick to secure a rental after the number of rental listings fell 5 per cent nationwide on last January."
A Rotorua house hunter, who wanted to remain anonymous, said he hadn't thought the rental crisis was valid until he faced it himself.
The man, his wife and two children were forced to look for a new home when the house they had been renting for four years was sold.
"I'd always thought that it was the people applying, their own doing," he said.
"I work fulltime, my wife works fulltime and we have two beautiful children. I thought I'm a model tenant."
However, he said he had regularly shown up to house viewings with more than 40 people.
"We got turned down from five or six houses and I started to panic."
The family finally got a three-bedroom home and moved in a week ago but the difference in price was drastic.
"We were in our last house for four years and we'd only had one price increase. We were paying $285," he said.
"[That] $285 is outstanding rent but I was surprised by the fact we now pay $400."
Rotorua Rentals co-director Richard Evans said there was a shortage of rental properties under the $300 mark.
"The average house most people want is around the $300 to $350 range. I've got nothing available under $450 a week," he said.
"I've put an ad up for a house in Reporoa, three bedrooms, garage - a nice modern home. That went online last night and there were 17 email inquiries before midnight."
Evans said he expected demand for rentals to slow in the winter.
"There won't be so many people looking. It's always the way. We'd expect a drop off during June and July of about 15 per cent."