The Nerazzurri, along with city rivals Milan, have plans in place to build a state-of-the-art stadium to replace San Siro and renovate the surrounding area.
But speaking on Thursday, Sala revealed the project is on hold until Inter's ownership situation becomes clearer.
Current owners Suning, who acquired the club in 2016, are reported to be looking to find a buyer amid financial uncertainty.
"I think that until Inter clarifies its fate, things must necessarily be at a standstill for us," Sala said.
"The point is, and I want to say clearly to the people in Milan, that we are not just talking about the stadium, but a project in which half the investment is on the stadium and half on other things that make up the future of that area.
"It will mean that there will be, I assume, five or six years of work. I cannot entrust a district of the city for such a long period to a reality whose future ownership is not certain.
"I speak with respect of [Inter president Steven] Zhang, but they must necessarily clarify the future of the club, until then I think it's logical to stop."
However, Inter released a statement on their official website later on Thursday that was a rebuke to Sala's comments.
"FC Internazionale Milano has a glorious ultra-centenary history," the statement read. "It existed before Mayor Sala and will continue to exist when his mandate ends.
"We find the comments from the mayor of Milan offensive towards the owners, disrespectful towards the history and reality of the club and its millions of fans in Milan and all over the world, not to mention irrelevant with respect to the current administrative process on the new stadium for Milan project.
"If it is confirmed that Inter and the owners are not appreciated by the current administration, we will know how to take the consequent decisions."