A toddler who drowned in a backyard pool on Saturday afternoon was found "unresponsive" by an older child during a social gathering, NT police say.
Police and paramedics were called to the toddler's home in Katherine, about 315km south-east of Darwin, after the incident.
"It's understood the toddler was located by an older child and an off-duty nurse attempted CPR before paramedics arrived," detective senior sergeant Paul Lawson said.
"Resuscitation attempts continued but the little one was declared deceased at Katherine Hospital.
Police will now prepare a report for the NT coroner.