Housing and Health Research Programme senior research fellow Lucy Telfar Barnard, of Wellington, said she hoped the mandatory scheme would be in place by the end of this year.
She had been working with the council to overcome the reservations.
"Our legal advice is there are ways that they can make [it] mandatory.
"Our advice is yes they can.
"I accept that they don't think they do [have the power],'' Dr Telfar Barnard said.
When contacted, Dunedin Mayor Dave Cull said "the university's getting a little ahead of itself''.
"Before it can go to the next stage, it would have to come back to council and be costed, and even the next stage ... would still be a [voluntary] trial.
"I know enough about the law to know we can't impose it at a local level.''
The warrant of fitness involves basic standards for things like ventilation, hygiene, heating and safety.
Dr Telfar Barnard said the idea was to make the worst-quality homes habitable, and it would not be too onerous a task.
It was not an "all the bells and whistles'' standard, she said.
Inspections would only be initiated when a tenancy changed hands.
"A voluntary system doesn't work because the only people who comply with the voluntary schemes are the ones who are not currently the problem.
"We have pointed out that there are provisions that they can enforce that mean that the warrant of fitness can be mandatory,'' Dr Telfar Barnard said.
She would continue to work with the council to change its stance.
The researchers were having "similar issues'' with the Wellington City Council.
Last December, the Housing and Health Research Programme announced it would work with Dunedin and Wellington city councils to develop warrant of fitness schemes. Funded by the Health Research Council of New Zealand, it was allocated $1.4 million over five years as a study grant.
