Mr McDouall, who has dealt with tenancy issues through his role as a lawyer at the Community Law Office in Wanganui, and also as a landlord himself, said landlords could take advantage of lower house prices in Wanganui to buy numerous properties for the price of one house in other cities.
"It's almost the standard model for exploitation to buy a cheap house and do little to no maintenance, while getting rent that ticks down the mortgage."
He said guaranteed payments from Work and Income New Zealand were particularly attractive for landlords and, if the tenant complained about conditions, unscrupulous landlords could "turf them out and get another".
He said the Dunedin City Council was considering a local bill, which would allow the council to put a bill through Parliament, giving the council power to enforce a warrant of fitness on rentals in the city.
The city's Mayor, Dave Cull, said the council was trying to set a minimum standard for rentals especially in the area of insulation, heating and weather tightness.
Mr McDouall said many of Wanganui and Dunedin's rentals were similar in age and condition.