The mother of two young girls who died after being left inside a hot car south of Brisbane has been remanded in custody over their alleged murders.

Kerri-Ann Conley, 27, has been charged with two counts of murder, and also with possessing dangerous drugs and possessing utensils or a pipe.

She did not appear when her matter was mentioned in Brisbane Magistrates Court on Monday morning.

One and two-year-old sisters Darcey and Chloe-Ann died after they were found locked inside a black station wagon parked in the front yard of their family home in Logan, south of Brisbane, on Saturday.

Temperatures reached 31 degrees on Saturday and police said the little girls had been in the car for several hours.

Paramedics tried to revive the sisters, but they died at the scene.

Ms Conley  is the first person to be charged under Queensland’s new expanded definition of murder, which includes reckless indifference to human life.

Also on Monday, Queensland Premier Annastacia Palaszczuk  said the state’s child safety department had been engaged with the family and will now conduct a child death review, as is protocol.

Attorney-General Yvette D’ath will ask Cheryl Vardon, the Queensland Family and Child Commission’s principal commissioner, to investigate what happened.

Kerri-Ann Conley has been charged with the murder of her daughters.

Ms Palaszczuk said she would release those findings.

“The death of these two young girls is an absolute tragedy,” she said.

“I was heartbroken when I heard about it, I think everybody would be in exactly the same position.”

Child Safety Minister Di Farmer has said her department will offer police any assistance needed in their investigation.

Ms Conley will next appear in Beenleigh Magistrates Court on December 11.

A man was assisting police with their inquiries but is no longer being questioned.

A woman lays a bunch of flowers outside the home where the girls were found. Photo: ABC

Officers remained at the home on Sunday, piecing together what happened, as neighbours and community members left soft teddies and flowers at the front gate.

The black station wagon remained parked across the yard.

Education Minister Grace Grace said she expected state cabinet to be briefed on the case on Monday.

“Over the weekend everyone heard the tragic news and we were all desperately saddened by that news and hopefully we will get a briefing today at cabinet in relation to the circumstances surrounding it but clearly the police are conducting their investigation,” she said.

“I just couldn’t imagine what those two little girls went through.

“This is truly a tragedy and we should do all we can to ensure this never ever gets repeated again.”

-with AAP