A body has been found on the side of a state highway in the South Island, police say.

In a media statement, a police spokeswoman said the death was not believed to be suspicious.

The body was found in the treeline on the side of the road, near the intersection of State Highway 1 and Northpark Rd in Ashburton.

Police were called about 4.20pm and are now working to find the person's next of kin, the spokeswoman said.