They want the Darwin Festival, scheduled for August, to take a leading role in the battle against climate change by rejecting sponsorship from companies involved in fossil fuel extraction.
"Artists and audiences have made it clear that we will not accept arts and cultural institutions being used as a vehicle for the promotion of fossil fuels and the damage their use has on our collective future," the letter says.
Santos' sponsorship deal includes the naming rights to the opening night concert on August 4 in Darwin called Bungul, when Yolnu dancers and songmen will perform with the Darwin Symphony Orchestra.
The letter accuses the festival organisers of providing Santos, the nation's second-largest independent gas producer, with a platform that enables it to continue "harmful practices" damaging to communities, culture and climate.
"Fossil fuel sponsorship and messages promoting its expansion has no place in our arts, culture and public institutions," it says.
The group also calls out Santos over allegations it had not obtained consent from some Tiwi Islanders for exploration drilling on the Barossa offshore gas field, 300 kilometres north of Darwin.
It also raises concerns over gas fracking in the Beetaloo Basin, saying it will release greenhouse emissions with global climate consequences.
"Artists and Territorians should not be made complicit with this type of climate sabotage through Darwin Festival's choice to accept funds from Santos and other fossil fuel sponsors," the letter says.
"We don't want to see this good work and the festival's good name used as a vehicle for any future promotion and art-washing by fossil fuel companies which are doing irreparable damage."
The letter has 190 signatories, including those of Denise Quall, Mikaela Earnshaw, James Cubillo, Genevieve Grieves and Kamahi Djordon King.
Traditional owners will speak and perform on Thursday at a rally to launch the Darwin Festival Dump Santos campaign.
Santos said it had been supporting the Darwin Festival since 1996.
"It is part of our commitment to support the communities where we live and work," the company said.
"In the Territory, we employ more than 100 local workers and we have spent $20 million buying goods and services from 60 local suppliers this year."
Santos also defended its production of gas, saying it was a corporate leader in climate action with a clear climate transition action plan and a target of net-zero emissions by 2040.
"The International Energy Agency says that natural gas is critical to a lower-carbon future," it said.
The Darwin Festival has been contacted for comment.
