  We study branch structures in Grigorchuk-Gupta-Sidki groups (GGS-groups) over
primary trees, that is, regular rooted trees of degree $p^n$ for a prime $p$.
Apart from a small set of exceptions for $p=2$, we prove that all these groups
are weakly regular branch over $G''$. Furthermore, in most cases they are
actually regular branch over $\gamma_3(G)$. This is a significant extension of
previously known results regarding periodic GGS-groups over primary trees and
general GGS-groups in the case $n=1$. We also show that, as in the case $n=1$,
a GGS-group generated by a constant vector is not branch.
