More than 30,000 people have called for a stop to oil and gas exploration near the world-heritage listed Ningaloo area in Western Australia.
The federal government is considering industry nominations for potential offshore exploration and drilling, including large areas off the Ningaloo coast.
A consultation period has closed ahead of a decision on the approved areas next month.
Environmentalists have expressed concern in a letter to federal Resources Minister Keith Pitt and Environment Minister Sussan Ley.
The letter urges the government to "signal clearly to the oil and gas sector that it must scrap any plans it has to further encroach on the Ningaloo-Exmouth Gulf area, either with pipeline facilities or oil and gas exploration or drilling".
Project Ningaloo director Paul Gamblin said the "emphatic" community response could not be ignored.
"People are understandably shocked by these proposals," he said in a statement on Tuesday.
Stretching more than 300km across the WA coast and boasting one of the world's longest near-shore reefs, Ningaloo was added to UNESCO's world heritage list in 2011.
It is known for its annual whale shark migration and network of underground caves.
A proposed oil and gas pipeline fabrication facility and towing operation is also under consideration in the Exmouth Gulf.
A study last year uncovered a remarkable level of biodiversity in the remote gulf, including species of sea snakes previously thought to be extinct.
Australian Associated Press
Sign up for our newsletter to stay up to date.