HWASEONG, South Korea (Reuters) - In tears, Chae Sung-bum rushed to a battery factory on the outskirts of South Korea's capital on Tuesday hoping to find the body of his daughter, or at least the necklace that would identify her, after a deadly blaze there killed her and 22 other workers.

"My daughter used to say batteries are dangerous, dangerous," Chae said, adding that she called several days ago and talked about another fire at her factory.

He said his daughter, a Chinese national, was 39 and due to be married within a few months.

Most of the victims are yet to be identified because of the intensity of Monday's blaze and explosions.

Seventeen of those who died were Chinese, and one was Laotian. Most of them were temporary workers at the plant packing lithium batteries, run by a South Korea-based company, Aricell.

The National Forensic Service, police and the fire department are holding a joint investigation into the accident. Aricell has said the company had fully complied with safety procedures and training for workers.

Chae's daughter was among hundreds of thousands of migrant workers in South Korea who make up a large portion of the work force but also face a disproportionately greater risk of injury and death as they take on dangerous jobs shunned by many young South Koreans, according to experts and activists.

Foreign labour is an increasingly crucial part of the workforce in South Korea with its shrinking and aging population. The government is expanding foreign labour quotas to tackle a shortage of workers, especially at small factories, shipyards and farms.

A record number of 923,000 foreigners are working in South Korea, of which one-third are Chinese nationals of Korean descent, according to government statistics last year.

The foreign workers are almost three times more likely to die in industrial accidents as they work under more unsafe conditions than domestic workers, according to a study last year published in the Journal of the Korea Safety Management & Science.

The number of industrial accidents among foreign workers has increased to 8,286 in 2022 from 6,404 in 2012, with about 100 deaths every year, the labour ministry said.

Such data are leading activists to question why foreign workers are not receiving the same level of protection as South Korean workers.

"Laws and regulations are already there but the issue is lack of pre-emptive checks to see if these rules are implemented on the ground," said Choi Jung-gyu, a lawyer who specialises in labour issues.

"Every year more than 100 migrant workers die from workplace accidents. We need to protect their rights and safety, that is good for our national interests," Choi said, adding the victims from the battery plant fire might have been doing the "most dangerous" work without proper safety training.

China's ambassador to South Korea, Xing Haiming, visited the scene late on Monday and requested all necessary support be given to the Chinese victims and their families.

He said he hoped the fire would be "a painful lesson" for South Korean businesses to ensure the safety of workers.

Near the factory, a funeral home where the bodies of four foreign nationals were brought on Monday night was quiet with few visitors.

An official at the funeral home said the bodies were impossible to identify immediately.

($1 = 1,387.4900 won)

(Writing by Ju-min Park; Editing by Jack Kim and Raju Gopalakrishnan)

By Hyunsu Yim and Daewoung Kim