Director of Agile Property Services in Masterton Eric Voice said some Wairarapa rental properties were "real dives".
The worst Wairarapa rentals had leaks in the ceilings, and holes in the floors and walls.
But WOFs would end up being a blanket policy.
"It's one of those things where everyone's going to be punished for the sake of a few who are bad landlords.
"It's just another cost."
According to Trade Me property figures published last month, the average asking rent in Wairarapa in thethree months to December was $256 a week.
Dr Smith said the trial would find whether housing WoFs were practical and cost-effective.
Each home would have to pass a 49-point checklist every three years.
They would have to be insulated and dry, safe and secure, and contain essential amenities such as bathroom and kitchen facilities.
In six months, Housing NZ would report how many homes were up to standard and the cost of upgrading deficient properties. APNZ/APN