diff --git a/openerp/addons/__init__.py b/openerp/addons/__init__.py
index af080724136..f91d66eb7a7 100644
--- a/openerp/addons/__init__.py
+++ b/openerp/addons/__init__.py
@@ -779,7 +779,7 @@ def load_module_graph(cr, graph, status=None, perform_checks=True, skip_modules=
                 modobj.write(cr, 1, [mid], {'state': 'installed', 'latest_version': ver})
                 cr.commit()
                 # Update translations for all installed languages
-                modobj.update_translations(cr, 1, [mid], None)
+                modobj.update_translations(cr, 1, [mid], None, {'overwrite': tools.config['overwrite_existing_translations']})
                 cr.commit()
 
             package.state = 'installed'
diff --git a/openerp/tools/config.py b/openerp/tools/config.py
index 7d0b04739e4..7b0e560f4f6 100644
--- a/openerp/tools/config.py
+++ b/openerp/tools/config.py
@@ -217,7 +217,7 @@ class configmanager(object):
         group.add_option("--i18n-import", dest="translate_in",
                          help="import a CSV or a PO file with translations and exit. The '-l' option is required.")
         group.add_option("--i18n-overwrite", dest="overwrite_existing_translations", action="store_true", default=False,
-                         help="overwrites existing translation terms on importing a CSV or a PO file.")
+                         help="overwrites existing translation terms on updating a module or importing a CSV or a PO file.")
         group.add_option("--modules", dest="translate_modules",
                          help="specify modules to export. Use in combination with --i18n-export")
         group.add_option("--addons-path", dest="addons_path",
@@ -264,8 +264,8 @@ class configmanager(object):
         die(opt.translate_in and (not opt.language or not opt.db_name),
             "the i18n-import option cannot be used without the language (-l) and the database (-d) options")
 
-        die(opt.overwrite_existing_translations and (not opt.translate_in),
-            "the i18n-overwrite option cannot be used without the i18n-import option")
+        die(opt.overwrite_existing_translations and not (opt.translate_in or opt.update),
+            "the i18n-overwrite option cannot be used without the i18n-import option or without the update option")
 
         die(opt.translate_out and (not opt.db_name),
             "the i18n-export option cannot be used without the database (-d) option")