Two women have narrowly escaped death after their car plunged into an enormous sinkhole in Santa Cruz, Bolivia's largest city.

The incident happened early in the morning on a major thoroughfare as the asphalt suddenly gave way beneath the passing vehicle.

Firefighters pulled the two women, aged 47 and 49, from the car and they were taken to a hospital with non-life-threatening injuries.

A leaking water main undetectable from the surface weakened the ground beneath the street, municipal Public Works Secretary Freddy Arauco told reporters.

Meanwhile, prosecutors have opened an investigation after a 10-metre wide sinkhole swallowed up a half-dozen cars on a residential street in Rome.

No one was injured in Wednesday evening's collapse in the Balduina neighbourhood, but families in nearby buildings were evacuated as a precaution.

The ANSA news agency says prosecutors are investigating a property owner and the construction company responsible for work along the road.