Police say the father left his Castlerobin home in the Castlereagh area around 10.30 am this morning with his three-month-old child.
After placing the toddler in a rear car seat, the man got into the driver’s side of his green Volkswagen Golf only to be confronted by a male who punched him through an open window.
The thug demanded that the man take him to the Ravenhill Road via Forestside Shopping Centre and the Ormeau Road.
He was then told to drive down the Ravenill Road and park up at Dublin Street near the Annadale embankment.
The victim was ordered to go into the nearby post office with a bag and demand money from counter staff while the kidnapper waited in the car with the baby.
But when he returned to his VW Golf car, the kidnapper had gone and his baby was still in the back seat.
The alarm was raised and when police were arrived, the victim told officers that the kidnapper had poured an unidentified liquid over him.
Detective Inspector Harry Colgan of the PSNI’s Reactive and Organised Crime Branch described the incident as “despicable”.
He said: “While the suspect did not take any money, this was a despicable act carried out by someone with absolutely no regard for the safety of the victim or his child.
“We would appeal to anyone who was in the Castlerobin area and saw or heard any suspicious activity to contact us on the 101 non-emergency number.”
Alternatively information can be passed confidentially through the freephone Crimestoppers number 0800 555 111.