Two trucks and a car towing a caravan have all rolled off the road just east of Southern Cross on Thursday afternoon.
The incident occurred around 20km outside of the Wheatbelt town on the Great Eastern Highway at around midday.
Police said no one was injured in the incident, but the highway was closed in both directions while WA Police and Main Roads attended the scene.
A Main Roads spokeswoman said emergency crews did not currently have a timeframe to have the crash cleared, and said it could still take some time.
It is unclear at this stage how all three vehicles rolled.