Police say the drowning of two young children in Perth on the weekend is a tragic reminder of swimming pool safety.

The two boys, aged 18 months and 12 months, drowned in a backyard pool in the southern Perth suburb of Cooloongup.

It is believed the pool is surrounded by a safety fence.

A coronial inquiry into the deaths of the children is likely once Kwinana detectives have completed their investigations.

Inspector Gary Kosovich says the deaths of the toddlers emphasises how susceptible young children are around water.

"We would ask that people out there with pools... check and ensure that you have the right fences erected and that no small children, toddlers particularly, can gain access to your backyard where your swimming pool is."