Two more bodies of workers trapped in a high-speed rail tunnel in Nakhon Ratchasima were recovered on Friday morning.

The bodies of all three workers trapped at the construction site have now been retrieved.

Ekkarat Sriarayanpong, chief of the State Railway of Thailand (SRT) governor's office, stated that the last two bodies, both Chinese nationals, were found about three metres from the location where the first victim was discovered. 

The victims were identified as Hu Xiangmin, a supervisor, and Tong Xinlin, a backhoe operator. They were working inside the train tunnel when it collapsed on Saturday night.

The discovery of the two Chinese workers came a day after the body of another trapped worker from Myanmar was found.

Caretaker Interior Minister Anutin Charnvirakul, who went to the site in Pak Chong district to follow up on the 126-hour rescue operation, said rescuers had recovered the bodies of all three workers.

Doctors at Maharat Nakhon Ratchasima Hospital will perform an autopsy to confirm the cause of death, he added.

The collapse occurred about 1.5 kilometres from the entrance of the four-kilometre-long tunnel, near Khlong Khanan Chit train station in Pak Chong.

The tunnel is part of the Sino-Thai high-speed railway being constructed between Bangkok and Nong Khai province, which borders Laos.