Terrorism is the most pressing issue now and for the next five years but the West underestimates the size of the Syrian refugee crisis, according to a new report.

Despite millions forced to flee Syria and at least seven million internally displaced, the French, Germans, British and American public believe there are fewer refugees than statistics from organisations such as the UN show.

Nearly five million have been forced to leave Syria but many in the West think that only hundreds of thousands are escaping the war which raged for five years.

Forced migration was cited by the British public as well as those in Lebanon and Iran as the second most pressing issue facing humanity while Germany and France cited hunger as the world's second most important challenge.

The findings were published as part of the Aurora Prize for Awakening Humanity's first annual humanitarian index on Friday ahead of the ceremony on Sunday.

The prize recognises people whose actions have made a positive impact on saving people or advancing humanitarian causes and the selection committee includes actor George Clooney and former Irish president Mary Robinson.