Educators in NSW have become so obsessed with Australian history that students can pass through school without learning about the Holocaust, the head of the education department has lamented.

NSW Education Department head Michael Coutts-Trotter said he learned a month ago that the Holocaust had been omitted from the state's mandatory history course, he said in a speech to high school principals.

Professor of History and Politics at Wollongong University Gregory Melleuish said the country had become too obsessed with Australian history - to the detriment of an overall view of world events.

"We tend to look at thing like World War I and II as Australia's involvement rather than what was at stake, why did it occur and what was going on," he said.