Four Spanish nationals have been arrested in Australia\'s Queensland and charged with importing 300 kilograms of cocaine into the country, the Australian Federal Police (AFP) said on Monday. The AFP said police arrested four Spanish nationals and seized 300 kilograms of cocaine from a yacht in Bundaberg, Queensland over the weekend. It is believed to be the fifth largest cocaine seizure in Australia\'s history, with the confiscated drugs estimated to be worth up to 78 million AU dollars (80.6 million U.S. dollars). Authorities also seized more than 3 million AU dollars (3.1 million U.S. dollars) in cash during related search warrants carried out in Bundaberg, Sydney and the Gold Coast, the AFP said. The investigation involved collaboration between the AFP, the Australian Customs and Border Protection Service, Queensland Police Service and assistance from authorities in Vanuatu. The yacht, named Friday Freedom, left Vanuatu on October 14, and arrived off the coast of Bundaberg on the evening of October 20. It was crewed by two Spanish nationals, a 35-year-old man and 37-year-old woman. The AFP said two other Spanish nationals - a 38-year-old man who resides in Sydney and 39-year-old man who resides on the Gold Coast - traveled from the Gold Coast to Bundaberg on Friday, November 11 to meet the boat. Police arrested the alleged offenders on November 11 when an exchange of cocaine took place at the Bundaberg Port. The four Spaniards are due to appear in the Bundaberg Magistrates Court on Monday, to face charges relating to the import of a commercial quantity of a border controlled drug. Investigations are ongoing and police have not ruled out further arrests. \"This operation demonstrates that the AFP, with our international and domestic partners, has the capability, resources and commitment to successfully detecting and dismantling the most sophisticated organized crime groups,\" Assistant Commissioner Zuccato said on Monday in a statement.