The Australian Reptile Park says "extreme caution" should be taken as people enjoy the outdoors because warmer Spring days have already led to an increase in snake activity.

The park's head of reptiles Daniel Rumsey says NSW residents in both rural and suburban areas should be on the lookout.

"Snakes don't go out to harm humans, but if you get in their path or startle them, they will bite and it can be fatal," he said in a statement on Friday.

The park helps save about 300 lives each year through an antivenom program, but Mr Rumsey said basic awareness was also important.

He warned against letting grass areas grow out-of-hand and allowing wood, tin or other materials to build up in backyard piles.

"These habitats provide a safe house for snakes as they sit in stealth mode awaiting prey to feed, and if startled they will defend through biting."