The crocodile was caught 55km downstream of Katherine in the Northern Territory earlier this week.

The 3.3 metre male saltie was caught in a trap.

The capture comes despite the low flow of the river and the few crocs caught after two poor wet seasons in the Katherine region.

Senior NT Parks wildlife ranger John Burke said the capture of the saltie was a "serious reminder you are in croc country".

"Crocodiles can be found in any waterway in the Top End region and you should always be Crocwise."

Many people have remarked in the large numbers of people seen swimming in the Low Level Reserve because of the unseasonal heat and the dangers of crocodiles.

Because of border closures and the low numbers of nomads in the area, most of these people are believed to be Territorians taking advantage of $200 tourist vouchers.

"Never be complacent around the water and only swim in designated swimming areas or pools," Mr Burke said.