Plunket is worried changes to home-pool fencing legislation might have Parliament going off the deep end when it comes to children's water safety.

The Building Pools Amendment Bill has passed its second reading.

It could see requirements for latched gates and fences, reduced to the more vague guideline of a barrier.

Plunket's Advisor for Child Safety Sue Campbell said there is overseas research and literature that shows what is needed to keep kids safe around water, and we need to stick to it.

"Fences should have a secure gate. They should isolate the pool from the house. Ideally, they need four-sided fencing and there has to be a secure and self-latching gate.

"If all those things are there, that's the best barrier you can possibly have."

Campbell said children are attracted to water, and can drown quickly and quietly.