Police have issued warning against the public approaching a Perth man believed to be travelling with his missing mother.

Police say Denise Allan has not been seen or heard from since last Thursday, and they believe she is in the company of her 41-year-old son Carl.

The pair are believed to be travelling together in a Ford Ranger Raptor ute, with a black snorkel, roof racks, a roof-mounted tent and recovery track mounts installed.

Detective Senior Sergeant Steve Carter said police have warned the public not to approach the pair if sighted.

“All we have is information that they may present a risk to the community, and we’re better safe than sorry,” he said.

“We don’t want to take any chances.”

Carl is believed to be 190 centimetres tall with a medium build, fair skin, blue eye and brown hair.

His mother, 63, is about 72 centimetres tall with a medium build, with blonde hair and blue eyes.

“The family are concerned, and we are concerned, and that’s why we’re seeking the public’s help,” Carter said.

He confirmed they were known to police.

Anyone with information should contact Crime Stoppers.