As an administrator we need an option to globally disable creation of new repositories.  

We are looking for a feature flag/property to disable it globally somewhat similar to the property which disables global creation of personal repo's.

Work around:

To prevent a user from creating repositories, we need to set the user as Bitbucket User in  Global Permission. This type of user can only log in to Bitbucket and access projects which have explicitly granted permission to this role.