Another North Korean 'ghost ship' has washed up on Japan's shores, after dozens of abandoned boats landed in November.

One dead body was found on-board the ship, which was discovered on a beach in Kashiwazaki, a city on Japan's northern coast, early on Tuesday morning (12 December).

Alongside the body, a badge bearing the picture of North Korean leader Kim Jong-un was found, a police spokesman told CNN.

Another body was found about 650m away from the boat, but police could not confirm whether this person had been travelling on the vessel.

Three other bodies were discovered further down the coast, on a beach in the town of Fukuara. It is unclear whether these bodies are connected to the ship in Kashiwazaki.

It is the latest "ghost ship" to have drifted into Japanese territory in recent months. In November, a record 28 ships ran ashore, prompting concerns that Pyongyang has launched a spy campaign against Japan.

Since the start of 2017, 76 fishing vessels have ended up on Japanese shores. Some of the stranded vessels have been labelled "ghost ships" because of the skeletons found on-board.

Dead bodies have been discovered on at least five ships in the past month. Eight skeletons were found in the hull of a vessel that washed ashore on Miyazawa beach in northern Japan on 27 November.

The Japanese coast guard has tightened patrols in recent weeks amid fears that North Korean spies are sheltering on the stranded ships.

"The government is well aware that this is causing great anxiety to local people," Japan's Chief Cabinet Secretary Yoshihide Suga said after a ship bearing a North Korean military emblem landed on a Japanese island in late November.

"The police and coast guard... are working to clarify the situation," Suga said. "Once we have the facts, we will respond firmly."

Over the summer, the Japanese coast guard issued 820 warnings to North Korean ships that sailed into the Yamato Bank fishing grounds within Japan's economic zone, the Financial Times reported.

Professor Satoru Miyamoto, from Seigakuin University, told that there was no reason for concern and said the rising number of ships was likely due to an increasing demand for fish.

"The number of wealthy people is growing and they're seeking a healthy diet. Fishing is meeting that demand," he said.

He said the increase highlights Kim Jong-un's decision to "expand the fisheries industry as a way of increasing revenue for the military. They are using old boats manned by the military, by people who have no knowledge about fishing. It will continue."