The President of the Ports Authority, Joan Gual de Torrella and three other Directors have been arrested by the Guardia Civil.
An investigation into alleged corruption at the Ports Authority, or APB, in Palma was launched on Thursday.
The case is reportedly related to the alleged awarding of moorings in Minorca and tenders for public contracts.
Guardia Civil Officers are searching APB headquarters in Palma, Mahón and Ibiza and have reportedly confiscated some documents from the offices.
The investigation was authorised by the Prosecutor’s Anti-Corruption Office.