New evidence in Kathleen Folbigg inquiry 'fundamentally changes' circumstances surrounding children's death, inquiry told

Kathleen Folbigg has five years left to serve of a 25-year sentence. (AAP: Peter Rae)

New scientific evidence "fundamentally changes" the understanding of the circumstances around the deaths of convicted killer Kathleen Folbigg's daughters, a lawyer for the NSW Director of Public Prosecution (DPP) says.

Retired Chief Justice Tom Bathurst KC is hearing closing submissions after a long-running judicial inquiry into Folbigg's convictions for killing her four children in the New South Wales Hunter region between 1989 and 1999.