UPDATED 3.55PM: Canterbury Police are now heading up the frantic rescue of a man buried under a massive landslide.

He was engulfed when a rock slide this morning buried the excavator digger he was operating at Pyramid Valley Engineering limeworks in North Canterbury.

Inspector Corrie Parnell said they understand three excavators were operating in the quarry when the face they were working on subsided.

25 people are now on site attempting to dig him out, including Alpine Cliff Rescue, geo-technical specialists and representatives from Mines Rescue and Worksafe NZ.

Victim support is working with the man's family.