A man and a woman have been charged over the alleged domestic violence-related killing of a toddler, who died in a Sydney hospital after a mercy mission to fly him halfway across the state.

The two-year-old boy was taken to Griffith Base Hospital with significant head injuries on December 1.

He was airlifted hundreds of kilometres from there to the Sydney Children’s Hospital at Randwick for treatment, but he died two days later.

Police launched an investigation into the death and on Wednesday morning officers from a NSW Riverina-area child abuse squad arrested a 21-year-old woman and a 33-year-old man at a property in the Griffith area.

Both were charged with domestic violence-related manslaughter and refused bail to appear in Griffith Local Court on Thursday.

The woman was also charged with domestic violence-related assault for an alleged attack on a two-month-old baby in November.

Investigators previously carried out a line search at a rural property outside Griffith as part of their probe into the boy’s death.

They also appealed for information from anyone who had seen the child in the week before his death in the towns of Leeton, Binya or Griffith.

Police are still looking into the circumstances surrounding the death and anyone who can help has been urged to contact Crime Stoppers.

– AAP