Allowing the side of an infinity pool to count as a fence is among a raft of safety changes that opponents fear could lead to more children drowning.
An overhaul of the rules will mean spas with lockable covers won't need fencing, councils will do pool inspections every five years, and barriers other than fencing can surround a pool.
The Government says the changes will save money, improve safety by requiring all councils to inspect pools periodically, and reduce "often cumbersome" requirements on pool and spa owners.
"I have seen hundreds of examples of the current law requiring fences to be erected, where any common sense person would say that it is impossible for a child to get access, because there is a wall or another feature that makes it impossible," said Building and Housing Minister Dr Nick Smith.
However, a number of safety organisations and medical professionals have reacted to the wider changes with dismay.
