A man has been arrested by police after a pedestrian was killed in a hit-and-run crash in Perth's southern suburbs overnight.

WA Police said a car struck two people on Torbay Mews in Warnbro around 1:30am before the motorist drove off.

A man aged in his 40s died at the scene while another man aged in his 30s was taken to Royal Perth Hospital in a serious condition.

Less than two hours later, officers located the vehicle believed to have been involved in the crash and arrested the driver, more than 40 kilometres away.

"After 3:10am police located a 36-year-old man and a Ford Falcon in North Dandalup," a police spokesman said.

"He has been taken into custody and is currently assisting with inquiries."

Homicide detectives returned to the scene of the crash in Warnbro this morning as they investigated the man's death.

Anyone with information is urged to contact Crime Stoppers.