Police are appealing for dashcam footage after a disturbing video emerged of a road rage incident involving a machete in western Sydney.

In the footage, a man wielding a machete can be seen confronting the driver of a ute at the intersection of Glossop Street and the Great Western Highway in St Mary’s at about 5pm yesterday afternoon, smashing a window of the Toyota Hilux and damaging a side mirror before walking back to his Honda Civic.

“Oh my god,” the woman filming is heard saying in the video.

She was a passenger in a nearby car when the incident unfolded, and was too afraid to be identified.

”As soon as he was tapping on the window with the machete, I’m like ‘yeah, something’s going to happen’,” she told 9News.

“We have no idea what happened, why he did this… it was just so scary.” 

Police have since spoken to the man behind the wheel of the Hilux, who was uninjured in the attack.

Meanwhile, the alleged machete-weilder is behind bars.

Exactly what led to the attack remains unclear, with Nepean police appealing for other witnesses or anyone with dashcam footage to come forward.