A serious crash has closed State Highway 8 at Fruitlands, near Alexandra.

Emergency services were called the two-vehicle crash about 12.25pm and the highway is now closed between Butchers Point Rd and Conroys Rd.

It is understood three people have injuries - two are in a critical condition and one is moderate.

The serious crash unit has been advised and diversions are in place through Earnscleugh.

However, police encourage motorists to expect delays and postpone travelling if possible.