A Chinese welder has died after the mobile phone in his chest pocket exploded.

Chinese state media reported that Xiao Jinpeng was killed in June while working at the Yingpan Iron Ore Dressing Plant.

His Motorola phone apparently exploded, driving splinters of his ribs through his heart. The man died in hospital after emergency surgery.

"We are aware of an accident that occurred in Gansu at a welding operation," Yang Boning, a press officer for Motorola in Beijing, told Chinese state news organisation Xinhua.

"Up to now, preliminary evidence suggests that it is highly unlikely that a cellphone caused this accident. We are working with the Chinese authorities to determine and investigate the root cause."

Motorola has dispatched a team of experts from Germany to examine the phone for faults.

One possibility is that the high temperatures generated by welding caused the explosion. Phones using batteries from third-party suppliers have also caused severe overheating in the past owing to poor power management controls.