China's Jinjiang Group is in the spotlight after Brazil's labour authorities said workers at a factory it is building for electric vehicle maker BYD were victims of human trafficking working in "slavery-like conditions".

BYD has been building the factory with an annual capacity of producing 150,000 cars initially in Brazil, the Chinese EV giant's largest overseas market, as part of plans to start production there.

Announcement came days after labour authorities also said they found Chinese workers at factory in Bahia were victims of human trafficking.