A 500-METRE exclusion zone has been set up at the Coleambally tip, after an object was reportedly found on Tuesday morning.
Initial reports suggested the object could be explosive.
One Rural Fire Service (RFS) truck was called to the incident at the Martin Bell Road landfill site at 10.52am.
An RFS spokesman said crews had established a 500-metre exclusion zone and police had been called to help identify the object.
HAZMAT crews are also at the scene.
A NSW Police media spokeswoman had limited information about the incident, but said Murrumbidgee Shire Council were assisting.