diff --git a/addons/project_long_term/project_long_term.py b/addons/project_long_term/project_long_term.py
index 109f0c03c6f..0758d4181e2 100644
--- a/addons/project_long_term/project_long_term.py
+++ b/addons/project_long_term/project_long_term.py
@@ -267,7 +267,44 @@ class project(osv.osv):
                     'date_end': p.end.strftime('%Y-%m-%d %H:%M:%S')
                 }, context=context)
         return True
-project()
+
+    def map_phase(self, cr, uid, old_project_id, new_project_id, context=None):
+        """ copy and map phases from old to new project while keeping order relations """
+        project_phase = self.pool['project.phase']
+        project_task = self.pool['project.task']
+        # mapping source and copy ids to recreate m2m links
+        phase_ids_mapping = {}
+        project = self.browse(cr, uid, old_project_id, context=context)
+        if project.phase_ids:
+            for phase in project.phase_ids:
+                phase_default = {
+                    'project_id': new_project_id,
+                    'previous_phase_ids': [],
+                    'next_phase_ids': [],
+                    'task_ids': [],
+                }
+                # adding relationships with already copied phases
+                for previous_phase in phase.previous_phase_ids:
+                    if previous_phase.id in phase_ids_mapping:
+                        phase_default['previous_phase_ids'].append((4, phase_ids_mapping[previous_phase.id]))
+                for next_phase in phase.next_phase_ids:
+                    if next_phase.id in phase_ids_mapping:
+                        phase_default['previous_phase_ids'].append((4, phase_ids_mapping[next_phase.id]))
+                phase_ids_mapping[phase.id] = project_phase.copy(cr, uid, phase.id, phase_default, context=context)
+        if project.tasks:
+            # if has copied tasks, need to update phase_id
+            for task in self.browse(cr, uid, new_project_id, context=context).tasks:
+                if task.phase_id and task.phase_id.id in phase_ids_mapping:
+                    project_task.write(cr, uid, task.id, {'phase_id': phase_ids_mapping[phase.id]}, context=context)
+        return True
+
+    def copy(self, cr, uid, id, default=None, context=None):
+        if default is None:
+            default = {}
+        default.update(phase_ids=[])
+        new_project_id = super(project, self).copy(cr, uid, id, default, context)
+        self.map_phase(cr, uid, id, new_project_id, context=context)
+        return new_project_id
 
 class account_analytic_account(osv.osv):
     _inherit = 'account.analytic.account'