Human remains were found among underground electric cables in Thailand.

The bones were discovered by electrician Panuwat Chaloeisat, 26, during an inspection of the underground power wires in Samut Prakan province on January 9.

Metropolitan Electricity Authority staff had pumped the water to inspect the electric connection, but were shocked to find a skull and several bones submerged in the sewage.

Police Lieutenant Nattanicha Rerngkwan of the Phra Samut Chedi Police Station said cops received a report at 7 pm.

Officers arrived to investigate the scene. They later called volunteer divers, who descended down the manhole located next to a vacant lot, and collected the bones - including a skull, rib bones, and pelvic bone - in one hour.

A pair of black pants believed to belong to the deceased was also found inside.

Police Lieutenant Nattanicha said: 'We believe the body had been underground for around one to two months. We still don't know the dead person's sex. The bones were sent to the Forensic Institute for identification and to find the cause of death.'

Panuwat, the electrician who discovered the skeleton, said he was dispatched to the site to inspect chronic power outages plaguing residents since November last year.

He said: 'Our team went to check seven underground cable sites. It takes around seven to 10 days to inspect each site because we need to pry up heavy manhole covers and drain the water before going down.

'At the last area, we proceeded with pumping out water as usual, but we were surprised when a human skeleton surfaced. I don't know how it got there, because the opening is very narrow, and there were no other entrances or exits.'

Authorities said the deceased may have been trying to steal the cables, but was electrocuted or suffocated to death in the cramped space.

The police said they were checking missing people reports and publicising information to find leads on the dead person's identity.