Four beds at a new mental health emergency centre are expected to ease the burden on a Perth hospital that has about 12 patients a day walk through its doors for specialist care.

The state government said it would allocate $1 million to a new Mental Health Observation Area at St John of God Midland Hospital to cater for people with drug, alcohol and mental health issues.

St John of God Hospital, Midland.

Health Minister Roger Cook said the new facility would hopefully drive at-risk patients away from the emergency department, which had 71,000 people through its doors in the last financial year.

“Patients will benefit from being treated in a dedicated treatment area in a low stimulus environment," he said. "In addition, it will free up vital beds in the hospital's busy ED."