This is the moment a bemused man who went missing as a child 31 years ago is reunited with his parents with his mother bursting into tears at the sight of him and his father running over to hug him.

The reunion in the full glare of the TV cameras took place in Chenzhou, in Hunan Province, in China, on July 17, with the footage showing the man being given a big hug by his biological tearful mother and his dad.

The footage shows the man unsure how to react.

The reunion was all the more heart-wrenching after it emerged that the man's grandmother had spent years looking for him before she passed away without ever knowing if he was even alive.

Local media reports said that she even mentioned her missing grandson when she was on her deathbed.