Last summer, UNESCO called on Canada to do more to protect the world heritage site, following a proposed fracking operation which generated much public outcry and ultimately failed in 2013.
The letter is addressed to Premier Paul Davis and Prime Minister Stephen Harper, and touts the need for a permanent buffer zone outside of the boundaries of Gros Morne.
Thirty well-known Canadians have signed on to the letter, including musician Tim Baker; writers Lawrence Hill, Joseph Noyden and Lisa Moore; astronaut Roberta Bondar; and actor Greg Malone.
Malone thinks the country needs to commit to preventing future resource exploration in the area.
"If we can't protect the most brilliant places in our province and in our country, what are we doing," he said.
Neither Parks Canada nor the provincial government have yet said how they plan to respond.
The Canadian Parks and Wilderness Society (CPAWS) said both levels of government are waiting for the other to act.
CPAWS National Executive Director Érik Hébert-Daly thinks there is a need for leadership and political action on the issue.
"There's still some confusion that exists there between various levels of government about who should be leading," he said.
"No one can run roughshod over the other, so we do need them all at the table and start working on a solution."
The province has instituted a fracking moratorium while it conducts a review of the drilling process.