Photo: Massive crocodile spotted at Northern Territory fishing spot Shady Camp

A massive five-metre crocodile has been sighted in the waters of a popular fishing spot.

Orhan Yilmaz, 30, photographed the reptile as it was swimming in the mangroves in Shady Camp, a spot regularly frequented by anglers in the Northern Territory's Mary River National Park.

The images have emerged just months after a man drowned in a Northern Territory river after a crocodile flipped his boat.

Mr Yilmaz, a regular Top End fisherman, said he has seen the large crocodile a number of times while fishing in the area.

'I've seen bigger ones down in East Alligator but that's the biggest one I've seen down at Shady Camp,' he told NT News.

He added that he believes the crocodile is one of two in the area. The size of the second is unknown but it has reportedly been spotted at a nearby boat ramp.

Earlier this year a man drowned in a river north-west of Shady Camp after a crocodile flipped his boat.

The ABC reported how Noel Ramage, 75, drowned while pulling in crab pots in in Leaders Creek with his friend Ray McCumber, 73.

The duo had been warned by a fishing expert that they needed to be careful on the water because their boat was so small.

Croc Expert Grahame Webb confirmed to NT News that the photographed crocodile could be as big as five metres, was a male and also appeared to have a swollen and bloated stomach.

'It could be pushed out by taking some huge breath, which extends the area and exposes more of the skin to the sun to warm up, or it could indeed be very fat,' he said.

On Thursday NT Parks and Wildlife warned people to be vigilant when it came to crocodiles.

The post on their Facebook took place on the 37 year anniversary of the capture of a giant 5.1 metre saltwater crocodile named Sweetheart.

'Attacks on boats by saltwater crocodiles are not uncommon,' the post reads.

'Parks and Wildlife urge you to Be Crocwise while boating and fishing in all Top End waterways.'

They advise those using the waterways to assume crocodiles are always present, obey warning signs and never provoke or harass crocodiles.