A mother dropped her baby while riding a motorcycle then carried on home before shocked locals find him on a road.

Mattana Tanehaan, 30, was riding pillion going home on her boyfriend's motorbike after enjoying a festival on February 13 in Sa Kaeo province, Thailand.

The allegedly drunk woman claimed she fell asleep as she held the four-month-old boy between her and the rider before noticing the infant was gone upon reaching home.

She then called the police for help before they found him at the provincial hospital where the baby was taken by concerned locals who found him on the road.

Lieutenant Colonel Manop Keawwanich said: 'We received a call around 8 pm that a baby was found on a road near city hall. He was wearing a blue shirt and diaper and was taken to the hospital.

'After a few hours, a couple went to us looking for the baby so we told them where he was. We checked the CCTV near the city hall to see what really happened.'

The mother was reunited with her baby and was able to take him home after telling hospital staff what happened, but police said they will investigate whether there was neglect that caused the incident.

Officer Manop added: 'We already have the footage. If found that the couple had been neglectful of the baby, the mother could face criminal charges.'

The boy sustained a scratch on his head due to the impact of falling from the moving motorbike but he was now in stable condition and discharged from the hospital.