A woman jailed in 2003 over the death of her four children has been pardoned following a judicial review after new evidence suggested she did not kill the children.

Kathleen Folbigg spent 20 years in prison after a jury found she killed sons Caleb and Patrick and daughters Sarah and Laura over a decade, but a recent inquiry heard scientists believe they may have died naturally.

Folbigg, now 55, maintained her innocence throughout the trial, a 2019 inquiry into her conviction reinforced her guilt. However, a second inquiry 2022 after fresh evidence suggested two of the children’s deaths were caused by a genetic mutation, led to her being pardoned

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

New South Wales attorney general Michael Daley said the probe had found reasonable doubt in each conviction, adding it is “impossible not to feel sympathy” for Folbigg.

She was released from a prison in Grafton, a decade before her jail term was due to expire and five years before she would have become eligible for parole.

The unconditional pardon does not quash Ms Folbigg’s convictions, Mr Daley said. That would be a decision for the Court of Criminal Appeal, if Mr Bathurst chooses to refer the case to it – a process which could take up to a year.

If her convictions are overturned, she could then potentially sue the government for millions of dollars in compensation.