A dip in vaccination rates has been blamed for one of Australia's worst diphtheria outbreaks as the rare respiratory disease continues to spread.
Hundreds of cases spanning three states and a territory have been reported amid fears the highly contagious infection has claimed a life in an outback community.
Almost all the cases have involved Indigenous Australians, prompting health authorities to work with Aboriginal agencies to try to curb the outbreak, including provision of vaccines.
Diphtheria was a feared childhood disease and common cause of death in children until the 1940s, when vaccines were rolled out.
Immunisation expert Milena Dalton said the outbreak highlighted how quickly vaccine-preventable diseases could re-emerge when there were immunity gaps.
"Although diphtheria remains rare in Australia this outbreak shows it hasn't disappeared," she told AAP.
