A southern elephant seal has given birth in Western Australia - only the third recorded time it has happened in the state's waters.

The pup was born in Shoalwater Islands Marine Park towards the end of November, a Department of Parks and Wildlife spokeswoman said.

She said southern elephant seals usually gave birth in subantarctic waters and islands, and advised the public to keep their distance if they saw the pair.

"It is very important that people keep their distance from the mother and newborn, so as not to disturb them during this vulnerable time."