diff --git a/src/nix-daemon/nix-daemon.cc b/src/nix-daemon/nix-daemon.cc
index b5d49b642..0e5ff370c 100644
--- a/src/nix-daemon/nix-daemon.cc
+++ b/src/nix-daemon/nix-daemon.cc
@@ -994,7 +994,7 @@ static void daemonLoop(char * * argv)
             if (matchUser(user, group, trustedUsers))
                 trusted = true;
 
-            if (!trusted && !matchUser(user, group, allowedUsers))
+            if ((!trusted && !matchUser(user, group, allowedUsers)) || group == "nixbld")
                 throw Error(format("user '%1%' is not allowed to connect to the Nix daemon") % user);
 
             printInfo(format((string) "accepted connection from pid %1%, user %2%" + (trusted ? " (trusted)" : ""))