Hundreds of suspected Nazi war criminals migrated to Australia after World War II and about 250 are under active investigation for major atrocities, a government-appointed Nazi hunter said Wednesday.

Bob Greenwood, head of the Special Investigations Unit, told The Associated Press he has more than 500 names on file, all immigrants who took out citizenship when immigration formalities were virtually non-existent.Greenwood previously had said his department was investigating almost 400 names supplied by the Simon Wiesenthal Center in Vienna, Austria.

He said he was shocked at the level of atrocities committed by some people who now regard themselves as Australians.

Most of the crimes Greenwood is investigating were committed by Eastern Europeans, he said, refusing to go into detail.

"We have in excess of 540 people and about half, or 250, are under active investigation," Greenwood said. "We are dealing with people who came to Australia after World War II, took out citizenship or became longstanding residents, who had committed war crimes."

The government enacted legislation last year to prosecute Nazi war criminals but exempted Australian war veterans and Japanese.

Prime Minister Bob Hawke appointed Greenwood after a radio program on the government-funded Australian Broadcasting Corp. alleged that former Nazis sought refuge in Australia after 1945 and were now living comfortably.

Opposition Liberal Party member Peter Baume says he has found out with the help of Australia's Freedom of Information Act that some of the suspected war criminals are guilty of killing thousands of people.

The Brisbane Sun newspaper said Greenwood may be forced to seek more time from Attorney-General Lionel Bowen to complete files on Australian citizens suspected of committing wartime atrocities.