Four people have been injured in a crash between two vehicles on State Highway 83, between Omarama and Otematata.

Emergency services were called to the crash, where the highway intersects with Prohibition Road, at 12.35pm, after the two vehicles - one towing a caravan - collided.

Initial reports indicate two people are in a moderate condition and two people are in a serious condition, a police media statement said.

The Serious Crash Unit has been advised and traffic management is in place. Motorists should expect delays and avoid the road if possible.