An abandoned North Korean ship filled with rotting corpses of people who may have fled the country's oppressive regime has washed ashore in Japan.

The rundown vessel is just one of a number of mysterious boats which have made their way across the Sea of Japan and ran aground on the coast in recent years.

An investigation has now been launched into the most recent eerie discovery after yet another boat was found to be carrying severely decayed bodies.

A tattered North Korean flag adorns the ship, with the "Korean People's Army" written across the hull.

As the boats continue to travel hundreds of miles across the ocean and wash up on Japan's west coast, theorists have been attempting to piece together the pieces of the eerie puzzle.

According to the Japan Times, it is claimed the ships were crewed by men and women desperately attempting to escape Kim Jong-un’s oppressive regime in North Korea.

Fishermen who were unable to handle the growing pressure of a demand in stock may have succumbed and fled in the boats, the paper reports.

In search of freedom, theorists claim the defectors then meet their tragic fate at sea as the ships enter stormy waters.

Others claim the bodies of those on board the most recent ship were poor fisherman.

All the bodies were found to be wearing civilian clothes, with many of the corpses too decomposed to be identified.

Investigators are now working to identify the cause of the mysterious 'ghost' ships.

Experts were seen onboard taking images of those who lost their lives at sea.

Some smaller wooden boats have also washed ashore, with many being pulled from the water in pieces after a devastating battering by the ocean waves.