A 17-year-old boy has been refused bail after allegedly threatening a woman and two children before leading police on a 100km chase in western NSW.

Police were called to a carpark on Montkeila Road, Walgett, around 691km from Sydney, yesterday afternoon.

A 35-year-old woman had her car allegedly stolen by the teenage boy.

The woman reported to the police that she and her young children, aged two and four, were menaced by the boy, who allegedly brandished a machete and insisted she give him her car keys.

Police then saw the car travelling south on the Castlereagh Highway towards Coonamble, where police attempted to stop the vehicle.

The teenage boy refused to stop, so a pursuit was initiated that lasted 100km.

It ended when the police deployed road spikes around 20km north of Coonamble, and the 17-year-old was subsequently arrested.

The boy was apprehended and brought to Walgett Police Station, where he faced several charges, such as armed robbery, aggravated assault with the intention to use a weapon to take and drive a vehicle, and obstructing or resisting police.

He appeared before a Children’s Court today.