A French fisherman attacked by a 2.5-metre saltwater crocodile in the Top End says he has got a "few holes on the head" and some stitches.

But 29-year-old Yoann Galeran, who fought the crocodile off during the attack off the East Arnhem Land coast last night, says he is otherwise fine.

"I just feel that I've been lucky and I just think [if it was] a bigger crocodile, I maybe wouldn't have any head," he said.

Mr Galeran was with friends at a yacht club in Nhulunbuy last night.

The deckhand says it was already dark when he agreed to swim out to a dinghy moored about 20 metres offshore.

"I was swimming, and maybe four or five metres from the boat, I just feel like rocks hitting on my head and something strong and I just realise [it was] a croc," Mr Galeran said.

"I just had the feeling that if I want to fight for my life, I just need to move all my body as much as I can.

"He just hit me on the top, on the left side, and on top of my neck and tried to push me down in the water."

Mr Galeran says he hit out at the crocodile and managed to escape.

"I punched him anywhere," he said.

Mr Galeran's boss, Lisa Heathcote, says the crocodile has been lurking in the area for the past few weeks.

The manager of Arnhem Fisheries says she saw the fisherman when he came out of the water after fighting the reptile off twice.

"It's got him by the head and rolled him and his instincts kicked in and he's just started to punch into it. It released him but then it came back again," Ms Heathcote said.

"We've walked out on the back deck and Jo's standing there with a big grin on his face and blood pouring out of him."

Mr Galeran suffered wounds to his back, neck, and head.

Watch Commander Vicki Koum says he was treated for the puncture wounds, but was not seriously injured.

"He's very, very lucky that he managed to swim away - [the outcome] could have been a lot more dire," she said.

"It's just a reminder that we live in the Territory, and where there is water, we have crocodiles."