Up to 51 foreign boats -- including from Vietnam, Malaysia and China -- will be scuttled at several different locations over the next two weeks, officials said.

Over a dozen were scuttled Saturday near Pontianak, in West Kalimantan Province.

Fisheries minister Susi Pudjiastuti said the action was necessary to warn neighboring countries that Indonesia was serious about fighting illegal fishing.

"There's no other way," she said. "This is actually the most beautiful solution for our nation, but yes, it's scary for other countries."

She said Indonesia suffered great economic loss from lax regulations that gave leeway for foreign boats to fish in Indonesian waters.

Since president Joko Widodo took office in 2014, hundreds of captured foreign fishing vessels have been sunk -- more than half from Vietnam.

The practice was suspended for several months, but has resumed since last week when a Vietnamese coastguard boat rammed an Indonesian navy ship attempting to seize an illegal trawler.

A dozen fishermen were detained and remain in Indonesian custody.

"If we don't act firm, they will be even more daring. I believe these collisions will get worse one day, this will escalate," Pudjiastuti said.

Jakarta claims the area in the southernmost reaches of the South China Sea as its exclusive economic zone and two years ago changed its name to the North Natuna Sea in a bid to show sovereignty.

More recently, it inaugurated a new military base in the chain of several hundred small islands to beef up defences. The moves prompted criticism from Beijing, whose claims in the sea overlap Indonesia's around the remote Natuna Islands.