Dog owners are angry at Auckland City Council's support of a report that links dog droppings on sports fields to blindness in humans.
The city's community boards are reviewing the 75 parks where dogs can be exercised unleashed, following the public outcry over dog attacks.
Boards will release theirlists of leash-free areas this month for public comment.
But Dr Cathy Casey, who heads a group of 500 dog owners opposing tougher restrictions, said council officers were giving the boards substandard information.
Dr Casey said the council's environments group circulated a report from the Sports Turf Institute, which says allowing dogs on sports fields is a public health issue.
"The main health risk is from ingesting faecal coliforms but the most serious potential hazard are parasites, including toxicaria, that can cause blindness in humans," said the institute's scientific manager, Dr Richard Gibbs.
Dr Casey said it was doubtful this information had any relevance to New Zealand where dogs, particularly in residential areas, were normally treated for parasites.
Her group, DOG, had done its own research which suggested a low risk of contracting toxicaria from sports fields in New Zealand.
People would have to eat droppings containing the parasites' eggs and even then the risk of illness was low.
Dr Gibbs could not be reached for comment.
But council environmental health officer Jacqueline McDougall said each side had its own experts and their advice differed.
"We are happy with our facts and we have based them on studies from around the world and what other councils have done as well - no dogs on sports fields," she said.
The Sports Turf Institute provided documentation for the reasoning behind the ban.
"We also have incidences reported by control officers that people can't use sports fields because dog owners refuse to move off it."
Jacqueline McDougall said parks officers had complaints from sports clubs concerned at the amount of dog droppings on the fields and the impact this would have on the health of their players.
