Rangers are warning people to remain vigilant around Top End waterways after a huge saltwater crocodile was pulled from a trap near Katherine.

The 4.6-metre reptile is the largest of the 116 crocodiles caught by wildlife officers in the Northern Territory this year.

The monster croc was pulled out of a trap in the Katherine River, about 10 kilometres from the town of Katherine.

Ranger Joey Buckerfield says the crocodile was so heavy it took unusual measures to get him out of the trap.

"There were about six of us on the rope and we could not pull him out," he said.

"We ended up having to winch him out with the Toyota.

"A couple of times before we have had to winch them out or just pull them up steep embankments.

"This time he was just genuinely heavy - by our estimates between 600 kilograms and 700 kilograms."

Mr Buckerfield says a 3.4m saltwater crocodile was also caught about one kilometres downstream from the popular Wangi Falls in Litchfield National Park.

"Even though the wet season has finished and the dry season is here, crocodiles still inhabit waterways and all the remnant waterholes of the river systems," he said.

"Anywhere you go where you are likely to encounter crocodiles, whether it be fishing, boating or camping, we just ask the public to be croc-wise."

Meanwhile, police have downgraded a search for a fisherman missing from Elcho Island, who they suspect may have fallen victim to a crocodile.