A mother from Queensland remains under police guard in hospital with serious injuries.

The 36-year-old woman was charged with murder following a police investigation into the fatal house blaze in Toowoomba, which broke out just after midnight on Wednesday, May 7 at the family’s Harristown home, resulting in the death of three of her children.

Emergency crews arrived to find the house engulfed in flames.

Know the news with the 7NEWS app: Download today

A young boy was found dead near the front door, while his two sisters were pulled from the fire in critical condition and rushed to Queensland Children’s Hospital.

Both girls later died after being taken off life support.

Police allege the fire was deliberately lit by the children’s mother.

She has been charged with three counts of murder (domestic violence offence), three counts of attempted murder (domestic violence offence), and one count of arson.

Two other children and the woman’s 34-year-old partner survived the fire.

Police say there are no other suspects, though the investigation is continuing.

The woman, who is still seriously injured from the fire, did not appear in court when the matter was briefly mentioned this week.

Her lawyer told the court she had visited her in hospital.

She remains under police guard.

A full brief of evidence has been ordered by the end of July.

The case will return to Toowoomba Magistrates Court on August 19.