Mother and two children feared dead after car plunges into NSW floodwaters.

A mother and two children are believed to have died after their car veered off a bridge into the swollen Tweed River in northern NSW on Monday afternoon.

A nine-year-old girl was able to escape as the vehicle was swept into floodwaters near Tumbulgum and immediately ran for help, according to AAP.

“She was screaming her mum, little sister and older brother had gone into the river in the car,” a witness,  Thomas Grinham, told Seven News on Monday.

Other locals said they tried to help but could only see bubbles rising to the surface.

After a two hour search, SES boats managed to locate the submerged car using sonar equipment about five metres from the river bank at around 3.25pm.

“I really think it (what will) unfold this evening will be a very tragic event,” Assistant Commissioner Jeff Loy told reporters.

“We will all be hurting.”

Police said the car “should have never” been driving on the road due to the dangerous conditions, and a team of divers will be deployed to search for the family on Tuesday morning.

Feature image: Nine News