NSW Police has shared the vision of a ute and truck travelling in in Sydney's south-west on Saturday.

The video shows a larger truck travelling in the left lane next to a small truck which is swerving between the right lane and rest lane.

The ute then appears to accelerate to try and overtake the smaller truck in the rest lane.

The small truck appears to continue blocking the ute from passing in the rest lane before the dashcam footage cuts out.

The incident occurred southbound on the Hume Highway at Menangle, near the Partridge VC rest area about 6.45am on Saturday, May 9, 2020.

Officers from Traffic and Highway Patrol Command's Strike Force Puma have released dashcam footage in the hope of receiving help from the public to continue their investigations.

Traffic and Highway Patrol Commander Assistant Commissioner Michael Corboy said that while police had since spoken to the truck driver who captured the footage, they were appealing for further witnesses to come forward.

"This event could have quite easily added to the road toll, which already sits at 116 lives lost on NSW roads this year," Assistant Commissioner Corboy said.

"We acknowledge drivers may experience frustrating incidents while they are behind the wheel, nothing is worth putting lives at risk.

"Police are always monitoring social media to identify dangerous driving on the state's roads so that we can take action.

"The fact that we are regularly alerted to these sorts of incidents by members of the public shows that other road users have had enough; they are united with police in their intolerance for dangerous driving behaviour on NSW roads.

"As our investigations into this incident continue, I would encourage anyone who has footage of this event, or even those involved, to come forward to police," Assistant Commissioner Corboy said.