From July 1, pure-bred pit bulls will be classed as dangerous under new state legislation.

Once declared dangerous, a dog must be desexed and micro- chipped within 28 days at the owner's cost.

The Department of Premier and Cabinet claims the laws have been introduced to reduce the risk of dog attacks in the community.

But RSPCA state president Paul Swiatkowski said the animal was responsible for attacks on people and other animals, not the breed.

"Classifying dogs as dangerous should be done on an individual basis and not a breed basis," he said.

"If you look at the statistics, German shepherds and Rottweilers are actually involved in more attacks on people and other animals than pit bull terriers are.

"Pit bulls seem to be singled out mainly because of their potential to do damage ... if you are bitten by a pit bull, it can cause more damage than other breeds."

When the law comes into effect, pit bulls may no longer be bred in any Australian state.

The Northern Territory and ACT are the only places yet to classify the breed as dangerous.

From July, pit bull terriers must be muzzled in public while on a lead no longer than two metres, controlled by an adult. At home, the dog must be kept in an approved child-proof enclosure.

Councils would be able to detain pit bull terriers until a suitable enclosure has been built - with the dog held at the owner's cost.

If a suitable enclosure is not built, the dog could be destroyed.

It is understood that the above regulations, including desexing, would not apply to cross-bred pit bulls.

The stringent new laws also require all dogs in the state to be microchipped before July 1 next year.