Investigation underway, staff stood down after baby left alone inside Busy Bees daycare in Mirrabooka

Two staff have been stood down and an investigation is underway after a 16-month-old baby was left alone inside a daycare centre in Perth.

The child was left asleep in the nursery by staff, who closed up and left the Busy Bees at Mirrabooka last week on Monday.

The mother arrived about closing time to see the lights turned off and the doors locked, sparking concern and urgent phone calls.

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A short time later, staff returned and located the baby asleep in the cot unharmed.

Busy Bees have launched an internal review and stood down two staff members until the investigation is completed.

"We respect the privacy of the family involved and have been supporting them directly," Busy Bees said in a statement to 9News.com.au

"The safety and well-being of the children in our care is our top priority and we are taking this matter very seriously.

"A comprehensive internal review is currently underway to understand how this occurred, including a full review of our policies and procedures."

Busy Bees is also working with the WA Education and Care regulatory unit and will implement any measures recommended to them.