Police are investigating after a man was found critically injured in Bethlehem overnight.

Police said they were called to the State Highway 2/Te Paeroa Rd roundabout at midnight after a person was discovered injured on the road, a police spokesperson said in a statement to SunLive.

“State Highway 2 was closed while the Serious Crash Unit conducted a scene examination and reopened about 5am.

“Inquiries are ongoing to determine how the man was injured.”