About 4.30pm emergency services were called to Warne Street in Wellington after a red Holden Commodore reportedly struck five people.

NSW Ambulance paramedics treated an adult and four children at the scene. Two of the children, boys aged six and seven died a short time later.

A 34-year-old woman was flown to Westmead Hospital where she remains in a stable condition.

A 10-year-old boy sustained serious leg injuries and was flown to the Children's Hospital at Westmead, where he remains and is undergoing surgery.

A nine-year-old boy sustained minor injuries and was taken to Orange Hospital.

He has since been released.

POlice said the driver of the vehicle allegedly left the scene.

Inquiries led officers to a home on Elizabeth Street, Wellington, about 8.40pm where a 25-year-old man allegedly attempted to run from police.

Following a short foot pursuit, he was arrested in a laneway behind the property.

During a search of the man, police allegedly seized a prescription drug. He was taken to Dubbo Hospital for mandatory blood and urine testing before being taken to Dubbo Police Station.

He has since been charged with dangerous driving occasioning death-drive manner dangerous, negligent driving (occasioning death), negligent driving (occasions grievous bodily harm), dangerous driving occasioning grievous bodily harm-drive manner dangerous, cause bodily harm by misconduct, in charge of motor vehicle (x2), never licensed person drive vehicle on road, fail to stop and assist after impact causing injury (x2), fail to stop and assist after vehicle impact causing death (x2), fail to stop and assist after vehicle impact causing grievous bodily harm, and possess prohibited drug.

He was bail refused and will face Dubbo Local Court on January 7.

Orana Mid-Western Police District Acting Superintendent Natalie Antaw said the incident had been a "complete tragedy" for the family and township of Wellington.

"It's been a tragic incident involving young children, which makes it all that more difficult," she said.

"Our hearts go out to the families of the children and also the town of Wellington."

Acting Superintendent Antaw said Lifeline at the Wellington Visitors Information Centre was available to support those in the community affected by the tragedy.

"Today myself and the region commander have been in contact with other emergency service workers including hospital and ambulance services who were also involved in responding to yesterdays collision," she said.

"We would be encouraging anybody who is feeling traumatised as a result of the incident to get in contact with their GP and seek medical help."

Police said they had been in contact with the family and would be offering as much assistance to them as they could.

"We have liaison officers in contact with the family, obviously they're grief-stricken in relation to the tragedy and the loss of their children and we will be offering our assistance to them as well," Acting Inspector Antaw said.

She said police would follow up reports the driver was doing burnouts in the street before the crash.

Investigators were still awaiting the results of the drug and alcohol testing.

Anyone who has any information or dash-cam footage that may assist police with inquires should contact Wellington Police Station or Crime Stoppers.

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