Heidi Strbak, 37, was sentenced on Friday to five years in prison after pleading guilty to the manslaughter of Tyrell Cobb.

In 2017, she received a nine-year jail term for the crime, but that sentence was set aside in March after a High Court appeal.

Strbak sobbed as Brisbane Supreme Court Justice David Boddice re-sentenced her after a four-day contested sentence hearing in October.

Justice Boddice immediately suspended the five-year sentence, taking into account the 1148 days Strbak has already spent in custody.

Tyrell died on the Gold Coast in May 2009 after Strbak and her then de facto husband Matthew Scown failed to seek timely medical treatment for the sick boy.

He had been vomiting following a blow to his abdomen, which tore open his small intestine.

By the time paramedics were called, Tyrell was unresponsive and never regained consciousness.

An autopsy revealed 70 bruises and abrasions, as well as a cigarette lighter burn on his ankle.

Justice Boddice said Scown and Strbak were the only people who had the opportunity to inflict two deliberate blows that caused Tyrell's death.

But he found the Crown hadn't been able to prove to the "requisite standard" that Strbak was to blame.

Justice Boddice rejected Scown's evidence during the hearing, but found Strbak was "negligent" by not seeking medical help for Tyrell.

He said her conduct involved serious criminal behaviour and she had "failed dismally" as a mother.

Justice Boddice said while Scown also cared for Tyrell, he was not the boy's parent.

"Your failure to provide the necessities of life to your own child represents a far greater breach," he told Strbak.

Australian Associated Press