Scribus can be automated using the powerful Python language via the scripting API. The reference manual can be viewed by selecting Help->Scripter Manual from the Scribus menu. (On Windows select Help -> Scribus Manual and navigate to For Developers -> Scripter API)
Scripting functionality will only be available if your version of Scribus was built to include it. Some binary packages (rpms, debs etc) don't include it and scripting functionality will therefore be unavailable.
It is also possible to automate Scribus in C++ using the Plugin Architecture.