Shark alarms will be installed at two popular Perth beaches after successful trials in the state's South West.

Nine News Perth reported the Town of Cambridge had plans to place four of the alarm systems, which will operate 24/7, along City Beach and Floreat Beach by spring.

The alarms will be installed at City Beach and Floreat Beach

The solar-powered systems will automatically sound an alarm and flash red when a shark is spotted or a tagged shark is detected in the area.

The council decided to fund the alarms, which cost $7,500 a year to hire, after being approached by the City of Perth Surf Lifesaving Club.