For the first time a dollar-figure value of the at-threat Great Barrier Reef has been revealed with new research showing the 2300-kilometre reef is too big to fail.

A Deloitte Access Economics report to be released at Hamilton Island on Monday calculated the reef was worth $56 billion.

The 90-page report also gauged how Australians and international visitors valued the Great Barrier Reef with two thirds of the 1500 respondents saying they were willing to pay to protect it.

Almost three quarters of Australians and over half the international respondents named the reef as the iconic Australian UNESCO World Heritage natural site.