Society of Paediatric Surgeons president Neil Price said members were concerned that the changes "are motivated solely for financial reasons and will put children at risk".
The Ministry for Business, Innovation and Employment estimates the new legislation will save $17 million in compliance costs, and save a further six lives per 10 years, based on the assumption that monitoring will be extended to the approximately 20 per cent of pools not currently inspected. Some councils inspect pools every three years, while others have no periodic inspections.
Dr Price said the improved-safety claim was "completely fallacious", and the Office of the Children's Commissioner labelled it unsound.
That was because the frequency of inspections for pools currently inspected (such as within Auckland Council) would reduce - increasing the risk that faulty gates and other problems are not picked up.
The Chief Coroner, Judge Deborah Marshall, while supportive of the bill overall, submitted that five-yearly inspections were not adequate.
National MP Paul Foster-Bell said modern homes "often have things like infinity pools, with a vertical barrier at the edge of the pool that no child could possibly climb over".