No, there aren't such chlorine tablets for a spa -- there are Trichlor tablets, but they dissolve too quickly in the hot water of a spa. There are some products that use Trichlor in special feeder for spas but many spa manufacturers void their warranty if you use them mostly because you can get the pH too low if you aren't adjusting it regularly. For spas, there are bromine tablets you can use in a floating feeder, but that is, of course, bromine.
