The last surviving crew member of the Enola Gay, the plane that dropped the first atomic bomb on Japan near the end of WWII, has died aged 93.

Theodore Van Kirk, also known as "Dutch", died on Monday of natural causes at the Park Springs Retirement Community in Stone Mountain, Georgia.

Mr Van Kirk, the crew's navigator, was 24 years old when the B-29 dropped "Little Boy" on Hiroshima at 8:15am on August 6, 1945, 69 years ago next month.

About 78,000 people were killed instantly, a number that almost doubled by the end of the year.

It was the first time in history an atomic bomb was used in combat.

The second was three days later at Nagasaki, where some 80,000 were killed. Soon after Japan surrendered, ending World War II.

In an interview long after the historic moment, Mr Van Kirk defended the bombing.

"Everyone condemned it, especially the young people," Mr Van Kirk said.

"They don't study it enough to know why we dropped the bomb, and why we dropped the bomb was there was a war going on and the only way I know how to win a war is to force the enemy to submit."

Many people viewed the crew as war heroes who saved the lives of Americans by sparing them an invasion of the Japanese mainland.

A funeral for Mr Van Kirk has been scheduled for August 5 in his hometown of Northumberland, Pennsylvania.

ABC/AFP