She had been swimming with family members at Mango Creek near the remote Aboriginal community of Nganmarriyanga – also known as Palumpa – 350km south-west of Darwin.
It was initially reported by family members as a crocodile attack.
“The child disappeared and they notified other family who were able to notify and contact police,” Senior Sergeant Erica Gibson told ABC Radio Darwin this morning.
“It is just simply a really tragic event not only for the family but for all responding frontline police officers who were there assisting the family.”
She said the whole community was “extremely distressed”.
A boat and a helicopter have been assisting in scouring the creek for any signs of the child, while police worked through the night with a crocodile management team to watch for crocodile sightings.
No crocodiles have been sighted in the immediate surrounds of where the girl disappeared.
Police Minister Brent Potter said yesterday afternoon that the Search and Rescue team had been authorised to remove the crocodile in order to allow for the search to safely continue.
“It’s probably safe to say we’re in the recovery stage,” he said.