Jakarta. The Foreign Affairs Ministry said Chinese authorities are continuing investigation into the sea burials of Indonesian crew workers on Chinese fishing vessels last month.

"Our embassy in Beijing sent a diplomatic note to the Chinese Foreign Ministry on May 19. They informed us the investigation was still ongoing," the ministry's citizen protection director Judha Nugraha said on Wednesday.

A video posted on Facebook by Suwarno Cano Swe on May 15 showed the dead body of another Indonesian fisherman, identified by his initial H., being dumped into the sea from a different Chinese fishing boat.

H. died after allegedly being physically abused on the boat, where the working condition was described as slave-like. 

Suwarno said H. was repeatedly hit with wood planks, steel rods, glass bottles and electrocuted.

"He died on Jan. 16 and was dumped overboard in Somali territorial waters," Judha said.

At least three other Indonesian crew workers had died on Chinese fishing vessels after receiving inhuman treatment and had their bodies thrown into the sea. 

Around 50 other Indonesian crew workers have been forced to work in slave-like conditions on other Chinese fishing vessels.

Judha said the ministry is having trouble tracking Indonesian crew workers on foreign fishing boats since many of them are undocumented.

"Many of these migrant workers are not documented in our database. They don't know how to register in the system when they work abroad," he said.

Migrant Care Executive Director Wahyu Susilo said many agencies send these crew workers to work on boats all over the world without going through the official red tapes. 

The procedure to earn a permit to work abroad from the Indonesian government is complicated. Applicants must submit multiple documents to the Workforce Ministry, the Indonesian Migrant Worker Protection Agency (BP2MI) and the Transportation Ministry.

"The bureaucracy is complicated and many workers don't have the required documents. They look for a shortcut and often fall prey to human trafficking," Wahyu said.

Wahyu said Indonesia should issue a government regulation to protect migrant workers in the maritime sector.

Currently, a total of 2.9 million Indonesians work abroad, of which 9,404 are documented ship crew workers.