Kathleen Folbigg: Woman jailed over infant deaths has convictions quashed

A woman once labelled "Australia's worst female serial killer" has been cleared of killing her four children.

Kathleen Folbigg's convictions were quashed by the New South Wales Supreme Court on Thursday, which found the evidence originally used to convict Ms Folbigg was "not reliable".

The 56-year-old was pardoned by the state government in June, after spending 20 years in prison.

Ms Folbigg has always maintained her innocence.

Her case - which has since been described as one of the greatest miscarriages of justice in Australian history - concerned the sudden deaths of her four children Caleb, Patrick, Sarah and Laura.

Each child died suddenly between 1989 and 1999, aged between 19 days and 18 months, with prosecutors at her trial alleging she had smothered them.

In 2003, she was sentenced to 40 years in jail for the murders of Sarah, Patrick and Laura, and the manslaughter of her first son Caleb.

Earlier this year, a landmark inquiry into her case concluded there was reasonable doubt over Ms Folbigg's guilt, due to scientific evidence that her children could have died of natural causes because of incredibly rare gene mutations.