Sisters drown in backyard pool after going out to play after lunch

Two young sisters have tragically drowned in a backyard swimming pool in Brisbane's south.

The girls, aged three and four, had been eating lunch at the property in Kingston before the tragedy occurred at 1.30pm on Tuesday afternoon.

According to reports, the girls were found in the pool by their five-year-old sister with paramedics quickly called to the scene.

The girls' parents pulled the duo from the water and performed CPR until emergency crews arrived.

Sadly both girls could not be revived and were pronounced dead at the scene.

"It's an immeasurable tragedy - how would you deal with something like this? The parents are distraught," inspector Glenn Allen said.

"We've got child protection investigators on scene and child safety will be notified."

Family members rushed to the property to comfort the girls' parents and their three surviving children.

The pool area where the girls were found is fenced. It is feared the girls either climbed over the fence or opened the pool gate.

According to police, the girls were eating lunch inside the home before the tragedy and it's believed the girls wandered into the backyard undetected.

The girls' deaths are not being treated as suspicious.

Shock figures show 280 people drowned in Australian waterways over the past financial year with 21 of those deaths children aged four and under.

Inspectors from the Logan council have attended the property to check the pool fence compliance.

That investigation will form part of the report to the coroner.