git-svn branches creation question

Is it possible to create and track new branches (or tags) using git-svn?

I know how to track existing branches, but new ones?

Some context. I'm tracking a CVS repository doing update from time to time on the master branch (using simply rsync and git-svn dcommit). Now I want to add a new tag for updates on the master. Currently I'm using svn copy. I'd like to do this directly from Git.

Thanks.