diff --git a/extensions/Makefile.in b/extensions/Makefile.in
index ca7b8088..13c58db6 100644
--- a/extensions/Makefile.in
+++ b/extensions/Makefile.in
@@ -27,6 +27,7 @@ INCLUDES	= -I. -I../include -I../libratbox/include $(SSL_INCLUDES)
 CPPFLAGS	= ${INCLUDES} @CPPFLAGS@
 
 SRCS =                          \
+  chm_adminonly.c		\
   chm_operonly.c		\
   chm_operonly_compat.c		\
   chm_quietunreg_compat.c	\
diff --git a/extensions/chm_adminonly.c b/extensions/chm_adminonly.c
new file mode 100644
index 00000000..f018de20
--- /dev/null
+++ b/extensions/chm_adminonly.c
@@ -0,0 +1,52 @@
+#include "stdinc.h"
+#include "modules.h"
+#include "hook.h"
+#include "client.h"
+#include "ircd.h"
+#include "send.h"
+#include "s_conf.h"
+#include "s_user.h"
+#include "s_serv.h"
+#include "numeric.h"
+#include "chmode.h"
+
+static void h_can_join(hook_data_channel *);
+
+mapi_hfn_list_av1 adminonly_hfnlist[] = {
+	{ "can_join", (hookfn) h_can_join },
+	{ NULL, NULL }
+};
+
+static int
+_modinit(void)
+{
+	chmode_table['A'].mode_type = find_cflag_slot();
+	chmode_table['A'].set_func = chm_staff;
+
+	construct_noparam_modes();
+
+	return 0;
+}
+
+static void
+_moddeinit(void)
+{
+	chmode_table['A'].mode_type = 0;
+
+	construct_noparam_modes();
+}
+
+DECLARE_MODULE_AV1(chm_adminonly, _modinit, _moddeinit, NULL, NULL, adminonly_hfnlist, "$Revision$");
+
+static void
+h_can_join(hook_data_channel *data)
+{
+	struct Client *source_p = data->client;
+	struct Channel *chptr = data->chptr;
+
+	if((chptr->mode.mode & chmode_flags['A']) && !IsOperAdmin(source_p)) {
+		sendto_one_numeric(source_p, 519, "%s :Cannot join channel (+A) - you are not an IRC server administrator", chptr->chname);
+		data->approved = ERR_CUSTOM;
+	}
+}
+