A mother and her son have been rescued after they were swallowed in a sinkhole that opened in the middle of a road in Romania.

Surveillance camera footage captured on Orhideelor ​​Street, Bucharest, showed the woman leaving her five-year-old boy at a kindergarten nursery on October 9 morning.

But just seconds after they exited the car, the cobbled street suddenly collapsed under their feet, drawing the boy into the massive pit that had opened.

The woman then jumped in to save him.

A nearby garbage truck teetered on the brink as the ground beneath its left wheels gave way, but somehow managed not to fall all the way in.

The truck driver quickly jumped out of the vehicle and pulled the boy and his mother from the sinkhole.

Authorities have begun investigations to determine what caused the road to collapse.

Bucharest city officials said: 'Before 1989, this site housed the Cigarette Factory. The ground collapsed over a utility pipe where a leaking pipe washed the earth away.

'Due to the combined weight of a parked car and a garbage truck from a waste management company that had stopped to collect trash, the ground gave way.

'The Sector 6 City Hall stated that it had no ongoing or past work in the area. The utility networks are managed by the Bucharest City Hall.'