Perth's beaches will soon be home to seals and sea lions as they rest before the breeding season, prompting a warning from the Department of Parks and Wildlife.

Australian sea lions, New Zealand fur seals and sub-Antarctic fur seals will be lazing at beaches in the Perth metro area and Southwest region in coming weeks.

Sea lion, Kangaroo Island, South Australia. Credit:SATC

The department is reminding people to leave the seals undisturbed and keep a safe distance from them.

Wildlife officer Cameron Craigie said people often attempt to "rescue" young seals and sea lions thinking they are sick or abandoned, when they are actually resting.