An abandoned newborn boy was rescued after he was left by his mum near a villager's home in Thailand.

The grime-covered baby boy with his umbilical cord still attached was discovered inside a plastic bag next to a septic tank at a house in Buriram province on June 11.

Police Captain Parinya Yingngam of the Khaen Dong Police Station said Khaen Dong Hospital staff notified the police that the foundling had been rescued at around 3:00 pm.

He said: 'We learned that the baby was the child of a secondary school student from a nearby village. She accidentally got pregnant and, fearing her grandmother's reaction, secretly gave birth and tried to dispose of the baby.'

Homeowner Banhan Sudto, 68, said he arrived home from tapping rubber trees when he heard crying near the side of his house. He initially thought the noise was coming from his pet cats.

He said: 'I listened carefully and thought it was strange because my cats do not usually cry at that time. I walked over to investigate and was shocked to see a baby had been left on my property.'

Banhan's neighbour Samarn Srimueang, 62, said she believed the mum had been trying to dump the boy inside the septic tank, but could not move the heavy concrete lid.

She said: 'The lid was slightly askew and there were signs someone had tried to move it. Whoever it was gave up and just left the baby near the septic tank.'

Meanwhile, hospital staff were monitoring the baby boy, who was deemed healthy with all of his organs intact.