Human remains have been fished out of the sea in north Auckland.

Retiree Paul Middleton, who has been travelling around the country in a camper van fishing, made the gruesome discovery by the Gulf Harbour ferry terminal on Tuesday afternoon.

"I saw a big lump out in the water that I thought might be a cow or something, so thought some kahawai might be hanging around nearby.

"As I got closer I realised it was a big black plastic bag," Middleton told Stuff.

According to Middleton, he unhooked his lure and pulled the bag towards him.

"There was plastic bag inside of plastic bag inside of plastic bag.

"To start with I thought someone had thrown away a big chunk of meat, but then I saw clothes on it - and then a hand," he said.

Middleton estimated what he thought was a body was wrapped in "at least" three plastic bags.

"I didn't want to disturb what might be a crime scene or whatever, so I did as much as I could to pull it up on the rocks.

"It was bloody heavy, I couldn't pull it all the way up so wedged it there and called the cops."

There were at least five police cars at scene.

Police have cordoned off a large part of the area and were seen taking gurney down to the water shortly before 5pm.

Police have been approached for comment.

This story was first published by Stuff