Social agencies worry as Trade Me says median figure now $420.
Residential rents have risen by 6.3 per cent in the year to April to a record-equalling median of $420 a week, a report says.
Head of Trade Me Property Nigel Jeffries said the rise equated to tenants paying $25 more a week in April 2015 than they did a year ago, or $1300 a year.
"Across the country, the rental market consistently delivered median rental growth north of 7 per cent year-on-year in 2015, accelerating on growth of about 5 per cent over the same period last year."
He said it was too early to assess the impact of the recent property and tax changes announced by the Government.
The figures are based on rents sought in about 11,000 listings on Trade Me each month.
Over the past five years, the company's index showed the median weekly rent across New Zealand had risen by 23.5 per cent from $340 a week in April 2010 to $420 last month.
Mr Jeffries said most of this increase was since mid-2013.
Four regions reported double-digit rental growth in the year to April 2015. Top was Gisborne (+20 per cent), followed by Marlborough (+12.3), Bay of Plenty (+10.9) and Southland (+10).
The median rent in the Bay of Plenty was $355.
Smaller properties of one to two bedrooms showed the largest rise in median rents in the past year, up 6.5 per cent or $20 a week.
Smaller homes in Auckland and Wellington had increases of 5.3 per cent and 4.8 per cent respectively, while Christchurch was more subdued at 2.1 per cent year-on-year.
For Auckland units, weekly rents reached a new record of $395 and were up $30 a week since April 2014.
The Auckland apartment market had a 5.9 per cent rise in median weekly rent in the past 12 months to a new record of $450, up from $400 two years ago.
Salvation Army social policy director Major Campbell Roberts said people at the bottom of the market faced not only a shortage of property but rents moving out of their reach.
Henderson Citizens Advice Bureau manager Heather Hahn said a large waiting list for Housing NZ homes had increased demand for private rentals of suburban homes and there were not enough of them. Open-home viewings for rentals were drawing 20 to 30 people.