Top Dutch soccer referee Rob Dieperink is dead ... just weeks after being dropped from the World Cup following a sexual assault arrest in the United Kingdom.

Dieperink's death was confirmed Monday by the Dutch Football Association, which released a statement saying it was "shocked and deeply saddened" by his passing.

The cause of death is unclear ... and police are reportedly conducting an investigation.

The ref was due to officiate World Cup games this summer, but was axed from the list after he was arrested on suspicion of sexually assaulting a teenage boy in the UK in April in a case that was ultimately dismissed.

The Daily Mail reports Dieperink was accused of unwanted touching and trying to entice a boy to his hotel room before a UEFA Conference League game between Crystal Palace and Fiorentina ... and was later arrested in front of other UEFA officials when he returned to the Netherlands.

The case was ultimately dropped due to lack of evidence.

The Dutch ref's death comes just days after the Egyptian International Team called for the investigation of French ref Willy Delajod -- Dieperink's replacement at the World Cup -- due to controversial officiating during the Argentina vs. Egypt Round of 16 match.

Dieperink was 38.

RIP