Wildlife rangers have hauled a four-metre male crocodile out of a creek in Darwin Harbour, which wildlife experts say is a reminder to some who think large crocs are not in the waters around the city during the cooler dry season.

The male crocodile measures 4.27 metres all up, and is the second largest of the 167 crocs caught in the Northern Territory so far this year.

A member of the public alerted the local croc management team to the animal caught in a trap in Sadgroves Creek, near the Darwin suburb of Bayview on Saturday.

"We quite often catch crocodiles in Sadgroves Creek, this animal just happened to measure over four metres which makes it quite a big guy," wildlife ranger Ian Hunt said.

Wildlife rangers say the fact the crocodile was caught so close to town was a warning to locals to be careful near waterways. ( NT Parks and Wildlife )

"The fact that it's so close to town is just a timely reminder that big crocs can inhabit all of our waterways.

"You have to be very careful to what you listen to in the Top End. You have to be very wary and be aware, basically, if you don't see a sign saying 'safe to swim', then it's not safe to swim."

Though the crocodile was mostly healthy-looking, he had two "big slices" in the middle of his tail that looked to be a few months old — which rangers believed was likely from a boat propeller.

"It was covered in barnacles, which means that animal has been swimming around in the ocean for some time — if he'd spent any time in the freshwater, they would have fallen off. So he's been in the salt water for a period of time, maybe a month or more," Mr Hunt said.

Graham Webb from Darwin's Crocodylus Park said most of the crocodiles that come into Darwin Harbour do so during the warmer months, when they are more active.

"I don't know why this animal would have suddenly moved and moved into here. I'd be 99.9 per cent sure that is one that's moved in rather than one that's been hiding under the wharf or something," he said.

The crocodile has been relocated to a crocodile farm south of Darwin.