A Syrian asylum-seeker who brutally beat his three-year-old son in an incident that shocked Greece has been handed a five-year prison term, the Greek news agency ANA said on Friday.

The 31-year-old was arrested on Tuesday after video footage, showing him thrashing the toddler at the Souda migrant camp on the island of Chios, went online.

Prosecutors said the individual beat the child "to try to pressure his wife," who had left him and had stayed in Turkey with another of their children, to join him and the boy in Chios.

The boy has been placed in the care of the Greek authorities.

Like most camps on Greek islands facing Turkey, Souda is overcrowded and living conditions are difficult. According to official figures, there are over 4,000 people in the island's camps in facilities nominally designed to handle just over 1,000.

They have been stuck there since the end of March, under an EU-Turkey deal for curbing the flow of migrants to Europe.

Those who were already on the island are supposed to be sent back to Turkey if their requests for asylum in Greece are rejected.