Wildlife rescuers in South Australia said a video of a newborn joey being rescued from its dead mother's pouch illustrates the importance of checking on roadkill.

The Fauna Rescue SA group posted a video to Facebook showing a newborn female kangaroo being rescued from inside her mother's pouch up to 24 hours after the older marsupial was killed by a car at the side of a South Australia road.

The group said the video was filmed by one of its off-duty rescuers who happened across the scene of the mother kangaroo's death.

The post said the rescuer had saved another joey from the pouch of a second kangaroo killed by a car further up the same road.

Fauna Rescue SA said the video illustrates the importance of checking recently-deceased marsupials for live babies, but the group cautioned members of the public not to attempt rescues on their own.

"DO NOT pull the joey out without training or advice -- you can cause serious damage to the mouth of a joey still attached to the mother's teat," the post said.