"If half of Ayers Rock was being chipped away by random tourists in the last 27 years, first of all I would hope we would be trying to stop that and secondly we wouldn't be trying to add to that," the University of Queensland professor said.
Scientists from James Cook University, University of Hawaii, University of Melbourne, UTS and CSIRO are among the league of professionals calling for action.
The letter calls on the Australian and Queensland Governments not to construct new ports outside existing industrial port areas and develop a new strategy to better manage coastal development.
The World Heritage Committee meets in 12 days and will discuss whether the reef should be listed as a World Heritage site "in danger", as recommended by Unesco, the environmental arm of the United Nations.
A Unesco report last month found 43 development proposals in the vicinity of the reef were under assessment and that the federal and state Governments had failed to improve water quality in the area.
Letter's key points
* Water quality has significantly dropped.
* Coral cover has declined 50 per cent in 27 years.
* Fish stocks have plummeted.
* New ports should be restricted to already established port areas.
* Cargo ship movements should be better managed.
* Independent research should be used to develop a coastal development strategy.
- AAP