After almost 20 years behind bars, new evidence casts doubt on the guilt of Kathleen Folbigg, who was convicted of killing her four children.

A judicial inquiry has been told the NSW Director of Public Prosecutions (DPP) has accepted new evidence, which points to the possibility of reasonable doubt.

Lead counsel assisting the inquiry, Sophie Callan SC has told the hearing that there are possible medical explanations for three of the children’s deaths.

The hearing also heard evidence questioning the validity of interpreting certain diary entries as admissions.