Comment 12 for bug 83604

Now that I look at it, gnome-system-tools has hard depends on neither ntpdate or ntp, but it suggests ntp. However, "suggests" doesn't make it installed by default, and time-admin in gnome-system-tools remains inoperative. It works if ntpdate works, though, even if the gnome-system-tools package doesn't depend on ntpdate in any way.

So, gnome-system-tools may also have a dependency bug, but that's a separate issue.