Dramatic rescue ... police at the scene.

Dramatic rescue ... police at the scene. Photo: The Western Advocate

A father held his toddler son's head above chilly water after his four-wheel-drive overturned in a river in the state's central west while he was testing its capabilities yesterday, police say.

The 13-month-old boy was in a stable condition in hospital this morning after being trapped underwater in the Macquarie River at Eglinton, on the outskirts of Bathurst, yesterday afternoon.

There was a person's life at risk and we tend to forget our own mortality and just dive in to try and save somebody  

His 28-year-old father was trying to cross the river in his Toyota Hilux about 3.30pm.

"[He was] testing his vehicle and attempting a water crossing," Chifley Local Area Command duty officer Inspector Colin Cracknell said.

"Approximately half-way across the river the vehicle became stuck in the soft sand base of the river and almost immediately rolled over on to its roof.

"The driver was able to escape from the vehicle and attempted to release his son. However, the baby was in a child restraint and he couldn't release the child restraint to recover the child."

Inspector Cracknell said the man held the baby's head above water until emergency services arrived.

Police officers dived into the water and cut the straps on the child restraint, before the baby was taken to Bathurst Hospital in a serious condition.

He was later flown to the Children's Hospital at Westmead, where he was breathing on his own and was in a stable condition in intensive care this morning.

The baby had been underwater long enough for his father to get out of the car and attempt to free him, Inspector Cracknell said.

"My understanding is that when he became aware that he was unable to release the child he then supported the child's head above the water as best he could.

"Police entered the water and also assisted to keep the child's head above water while another officer cut the harness traps to release the child."

Inspector Cracknell said overnight temperatures of about 5 degrees had made the Macquarie River very cold.

"The officers and the driver [also] would have had to contend with the current in the flowing river."

He said the site was a popular place for drivers to test the capabilities of their cars before four-wheel-driving expeditions.

"It's early days in the investigation so police are looking ... at all the information that led up to this tragic incident.

"Suffice to say it's not a regular road crossing. I believe it is an area that is used by four-wheel enthusiasts to test the abilities of their vehicles and practise their river crossings for when they are in off-road conditions.

"It's certainly something that we wouldn't recommend people be doing because of the potential dangers that are involved in that."

Inspector Cracknell also praised his officers' work.

"There was a person's life at risk and we tend to forget our own mortality and just dive in to try and save somebody."