AUSTIN, Texas—The chief executive of South by Southwest said organizers are unsure how they will keep the festival going after the city canceled it because of the novel coronavirus, which he said could cost them millions.

Austin officials on Friday pulled the plug on the tech, music and movie event, citing the threat of the coronavirus outbreak. The move dealt a devastating blow to the finances of the festival, whose insurance doesn’t cover disease-related cancellations, South by Southwest co-founder and Chief Executive Roland Swenson said in an interview Sunday.

Mr. Swenson stressed that organizers have every intention of continuing South by Southwest, or SXSW, which has taken place every year since its founding in 1987. But he said organizers were trying to assess how much funding it would lose as a result of the cancellation and were concerned it could run in the tens of millions of dollars.

“I am most worried about my people and what this means for their future, and I don’t know what that is yet,” Mr. Swenson said. “We are planning to carry on and do another event in 2021, but how we’re going to do that I’m not entirely sure.”

South by Southwest has grown from a local music festival into a major global event, bringing hundreds of thousands of people from around the world to Austin and pumping some $355 million into its economy, festival organizers estimate.