Mongrel Mob members who gathered at the site where a van carrying five people ploughed into the Wanganui River huddled together and barked like dogs as a child's body was removed from the water.

The bodies of 2-year-old Duane Richard Pauro and his 38-year-old mother Frances Te Kaawa were recovered from the river after the Subaru Impreza they were travelling in crashed on Sunday afternoon.

Three others - the 38-year-old male driver Donovan Tuirirangi and two teenage boys - managed to escape from the submerged car.

Witnesses said they looked shaken and were crying as they emerged from the water and stood watching the rescue attempts from the riverbank.

One of Tuirirangi's eyes looked bruised and swollen.

Police say the car, which was seen being driven erratically and at speeds of up to 100km/h in a 50km zone, was heading north along Anzac Parade at about 1.25pm when its tyre struck the kerb and deflated.

Tuirirangi, who was allegedly trying to overtake another car at the time, lost control and the car plunged down a bank into the river.

The child, Tuirirangi's nephew, was only in a seatbelt, not an approved carseat and was thrown into the water while his mother was believed to have been trapped in the car.

Senior Sergeant Shayne Wainhouse said several members of the public jumped into the water straight but couldn't help the child or his mother.

After the crash, relatives and friends, some of whom were gang members, gathered on the riverside as emergency services scoured the water.

They found Ms Te Kaawa's body soon after but had to call in the police dive squad to search for the child, whose father reportedly arrived at the scene distraught and screaming "my baby's in the car".

The car was pulled from the river at 7.15pm and about an hour later the dive squad found Duane's body 15m away.

A local resident said relatives were holding a service at the scene. Just as they finished the boy's body was found.

One witness said gang members barked like dogs - a typical Mongrel Mob behaviour - as the body was removed from the river.

Tuirirangi, who has been charged with careless driving causing death, appeared in the Wanganui District Court yesterday.

Up to 50 friends and family members were reportedly packed into the court's public gallery, including a number of Mongrel Mob members.

Tuirirangi was remanded in custody until his next appearance next month and police say further charges are expected to be laid against him.

Meanwhile, Palmerston North police say dental records may be needed to help identity a male who was killed when the car he was driving crashed into a culvert and caught fire at State Highway 56 near Palmerston North yesterday morning.

Senior Sergeant Sue O'Neil, Palmerston North Police Response Manager, said police were also investigating an earlier report of a car crashing into a fence about 10km south of the fatal scene.