Public servants and political staffers appear to have made tens of thousands of anonymous changes to Wikipedia that insult a world leader and a former prime minister, scrub embarrassing information and even claim the Holocaust was "justified".

The Department of Prime Minister and Cabinet has ordered the heads of the Defence, Foreign Affairs and Trade, Health, Agriculture and Parliamentary Services departments to urgently investigate possible breaches of government IT policy and report back in a week.

An analysis by Fairfax Media using the WikiWatchdog website – which tracks anonymous edits made to the online encyclopaedia and logs the internet protocol (IP) address the changes were made from – indicates 8790 pages have been anonymously altered by staff across major federal government departments over the past decade.

Wikipedia is one of the most popular websites in the world, with 5.2 million pages in English that anyone can edit anonymously or after creating a username and password.

