Police and coast guards continued their search today for a German tourist who plunged into the sea from a ferry in Thailand.

Florian Storz, 35, was travelling with his girlfriend when the vessel left the island of Koh Phangan in Surat Thani province on January 31 evening.

Passengers and crew were thrown into a panic around 15 minutes into the trip when the German national allegedly jumped overboard. The ship, named Racha 8, immediately turned around to search for the missing holidaymaker.

Officials are now continuing to trawl the region and have alerted all boats to keep a lookout for the holidaymaker.

Police Colonel Suparerk Pankosol, superintendent of Surat Thani Immigration, said he has also ordered immigration staff to help with the search.

He said: 'There has been no sign of the passenger since the incident happened. The seas are choppy at this time of the year.'

Police, marine officials, and rescue volunteers divided into teams on February 2 to find the tourist.

Rescuers scanned along the ship's route, coastal areas, and nearby islands, including Koh Tae Nok and Koh Tae Nai, but have failed to turn up anything on his location.

The search and rescue had been hampered by poor weather and visibility immediately following the incident. The operation is now on its third day, still with no sign of the German national.

Passengers onboard at the time said Florian, who was with his girlfriend, had plunged into the sea some 15 minutes after the ferry set sail for Koh Samui island.

Florian's girlfriend, who was not named by police, could not give a possible motive for her partner's sudden plunge into the sea.

She reportedly told officers they were enjoying their trip before the unexplained incident on the boat.

It is still unclear why he went overboard.

Police said that Florian had landed at the Suvarnabhumi International Airport in Bangkok on December 26. His visa was set to expire on February 2.