F1 chief executive Bernie Ecclestone announced last week that a deal has been struck in principle between the sport's two current Spanish hosts.
But Vicenc Aguilera, the Circuit de Catalunya president, told Mundo Deportivo newspaper: "We (Barcelona and Valencia) have two completely different business models, making the negotiations quite complex.
"We need to find the balance between the interests of Mr Ecclestone, Valencia and ourselves," he added.
He said that in the absence of a deal, Barcelona has the annual Spanish grand prix hosting rights through 2016.
But he acknowledged that alternating would be a "good solution" for all parties, "so I hope that in a couple of months we can make an announcement".