A Ukrainian cruise captain went on trial in Hungary on Wednesday over a collision on the river Danube last year that led to the deaths of 27 people, mostly South Korean tourists.

The Mermaid sightseeing boat carrying the tour group sank within seconds after colliding with the Swiss-registered Viking Sigyn river cruise vessel on May 29.

The disaster, on a busy stretch of the Danube in the heart of Budapest, was Hungary's worst boating accident in over half a century.

Only seven South Koreans were rescued, while 25 South Koreans including a six-year-old girl as well as the Hungarian captain of the Mermaid and one crew member died. A South Korean woman remains missing.

The recovered sunken Mermaid sightseeing boat as it was transported off the river Danube
The recovered sunken Mermaid sightseeing boat as it was transported off the river Danube AFP / FERENC ISZA

Yurij Caplinskij, 64, is charged with "endangering waterborne traffic resulting in multiple deaths" and 35 counts of failing to provide help.

During the opening hearing at a district court in Budapest, prosecutors said they were seeking a nine-year jail term and a ban from driving waterborne vessels for Caplinskij if he admitted all the charges.

The Ukrainian denied the charges and declined to make any further statement.

The captain of the Swiss Viking Sigyn cruise vessel Yuriy Caplinskij denies the charges against him
The captain of the Swiss Viking Sigyn cruise vessel Yuriy Caplinskij denies the charges against him AFP / STR

According to prosecutors, Caplinskij, the only driver of the Sigyn, did not concentrate on his duties for at least five minutes and was negligently unaware of the dangerous proximity of the Mermaid, failing to slow down and steer away from it.

"I didn't notice the boat," read a message he sent to his son minutes after the crash, according to case documents.

He then neglected his duty to provide help to those who fell in the water or were trapped on board the sunken boat, say prosecutors.

The 56-year-old Ukrainian captain of a second cruise vessel, the Viking Idun that was following the Sigyn, was also detained in January on suspicion of 35 counts of failing to provide help.

Some of the bodies were recovered dozens of kilometres south of the Hungarian capital.

Relatives of the South Korean victims did not travel to attend the trial because of the coronavirus epidemic, the judge said.

Journalists were allowed into the court briefly before the hearing began but are barred throughout the trial.

However, they are able to watch proceedings via video feed in a nearby room.

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