A small freshwater crocodile was blamed for biting a tourist on Wednesday.
NT Parks has closed Wangi Falls in Litchfield National Park for swimming as a result.
Freshwater crocodiles are often viewed as virtually harmless in NT waterways under most circumstances.
Only recently NT Parks closed popular Bitter Springs at Mataranka because of the sighting of a large freshwater crocodile.
A spokeswoman for NT Parks said Wangi Falls “is currently closed for swimming after reports that a small crocodile bit a man yesterday afternoon, resulting in minor injuries”.
The spokeswoman said rangers will survey the area tonight to ascertain species and size, however it is believed to be a freshwater crocodile less than a metre in length.
“For visitor safety and to reduce the risk of human interaction with wildlife, the waterhole will stay closed for swimming until all practical steps have been taken to capture and or remove the crocodile.
“Wangi Falls is closed for swimming; however the loop walks, viewing platform, picnic and barbeque areas and café remain open for public use.
“All other swimming holes in Litchfield remain open.”
For up-to-date information regarding access to parks and reserves administered by the Department of Tourism and Culture, visit nt.gov.au/leisure/parks-reserves