Indonesia detained 200 Malaysians found fishing illegally in its territorial waters on Wednesday, Reuters reported.

The move comes as newly-elected president Joko Widodo expressed a more assertive stance towards rampant illegal fishing in its waters which has caused a loss of US$24.7 billion (approximately RM92.1 billion) to the country annually.

The president, fondly known as Jokowi, said firm action was necessary to stem further losses, including sinking the illegal fishing boats on the spot.

“There is no need to arrest them [the illegal fishing boats]; just sink them,” Jokowi was quoted saying in a report by The Jakarta Post.

“Sink 10 to 20 [ships]. It would make them [the illegal fishermen] think. But, remember to rescue the crew on-board first,” Jokowi said.

Cabinet Secretary Andi Widjajanto told Reuters, he expects some 300 more illegal fishermen to be detained in the next few days.

"We are trying to send a clear message to our neighbours like Malaysia and China, which operate illegal ships in our territory, that this is not a normal situation for us,” Widjajanto said of the move which is expected to spark tensions in the region.

Indonesia, added Widjajanto, plans to lodge diplomatic protests with the countries involved in anticipating complaints over the capture of their citizens.

The largest economy in South East Asia is also planning to launch a new coastguard force in mid-December tasked with preventing piracy and illegal fishing, and safeguarding maritime borders, Reuters reported.

On Thursday, Maritime Affairs and Fisheries Minister Susi Pudjiastuti said the government would sign memorandum of understandings to combat illegal fishing with six ambassadors of neighboring countries, including Malaysia, the Philippines, Thailand, Vietnam, Australia and China on December 13.

“The six ambassadors have promised to help combat illegal fishing in Indonesia,” she told The Jakarta Post.