diff --git a/lib/moodlelib.php b/lib/moodlelib.php
index e932026d880..0da25cdb0b4 100644
--- a/lib/moodlelib.php
+++ b/lib/moodlelib.php
@@ -4432,19 +4432,7 @@ function complete_user_login($user) {
     // Queue migrating the messaging data, if we need to.
     if (!get_user_preferences('core_message_migrate_data', false, $USER->id)) {
         // Check if there are any legacy messages to migrate.
-        $sql = "SELECT id
-                  FROM {message} m
-                 WHERE useridfrom = ?
-                    OR useridto = ?";
-        $messageexists = $DB->record_exists_sql($sql, [$USER->id, $USER->id]);
-
-        $sql = "SELECT id
-                  FROM {message_read} m
-                 WHERE useridfrom = ?
-                    OR useridto = ?";
-        $messagereadexists = $DB->record_exists_sql($sql, [$USER->id, $USER->id]);
-
-        if ($messageexists || $messagereadexists) {
+        if (\core_message\helper::legacy_messages_exist($USER->id)) {
             \core_message\task\migrate_message_data::queue_task($USER->id);
         } else {
             set_user_preference('core_message_migrate_data', true, $USER->id);
diff --git a/message/classes/helper.php b/message/classes/helper.php
index 0c68fd74d4d..cf5a8b68b6d 100644
--- a/message/classes/helper.php
+++ b/message/classes/helper.php
@@ -330,4 +330,28 @@ class helper {
         sort($ids);
         return implode('_', $ids);
     }
+
+    /**
+     * Checks if legacy messages exist for a given user.
+     *
+     * @param int $userid
+     * @return bool
+     */
+    public static function legacy_messages_exist($userid) {
+        global $DB;
+
+        $sql = "SELECT id
+                  FROM {message} m
+                 WHERE useridfrom = ?
+                    OR useridto = ?";
+        $messageexists = $DB->record_exists_sql($sql, [$userid, $userid]);
+
+        $sql = "SELECT id
+                  FROM {message_read} m
+                 WHERE useridfrom = ?
+                    OR useridto = ?";
+        $messagereadexists = $DB->record_exists_sql($sql, [$userid, $userid]);
+
+        return $messageexists || $messagereadexists;
+    }
 }