diff --git a/manifests/agents/l3.pp b/manifests/agents/l3.pp
index 1795ca150..29024480d 100644
--- a/manifests/agents/l3.pp
+++ b/manifests/agents/l3.pp
@@ -80,7 +80,7 @@
 #   Defaults to $::os_service_default
 #
 # [*extensions*]
-#   (optional) L3 agent extensions to enable.
+#   (optional) List of the L3 agent extensions to enable.
 #   Defaults to $::os_service_default
 #
 # [*radvd_user*]
@@ -161,7 +161,7 @@ class neutron::agents::l3 (
     'DEFAULT/radvd_user':                   value => $radvd_user;
     'ovs/integration_bridge':               value => $ovs_integration_bridge;
     'agent/availability_zone':              value => $availability_zone;
-    'agent/extensions':                     value => $extensions;
+    'agent/extensions':                     value => join(any2array($extensions), ',');
   }
 
   if $::neutron::params::l3_agent_package {
diff --git a/spec/classes/neutron_agents_l3_spec.rb b/spec/classes/neutron_agents_l3_spec.rb
index 04113797d..f18dcb977 100644
--- a/spec/classes/neutron_agents_l3_spec.rb
+++ b/spec/classes/neutron_agents_l3_spec.rb
@@ -129,6 +129,26 @@ describe 'neutron::agents::l3' do
         should contain_neutron_l3_agent_config('agent/availability_zone').with_value(p[:availability_zone])
       end
     end
+
+    context 'with extensions in string' do
+      before :each do
+        params.merge!(:extensions => 'fip_qos,gateway_ip_qos,port_forwarding')
+      end
+
+      it 'configures extentions' do
+        should contain_neutron_l3_agent_config('agent/extensions').with_value('fip_qos,gateway_ip_qos,port_forwarding')
+      end
+    end
+
+    context 'with extensions in array' do
+      before :each do
+        params.merge!(:extensions => ['fip_qos', 'gateway_ip_qos', 'port_forwarding'])
+      end
+
+      it 'configures extentions' do
+        should contain_neutron_l3_agent_config('agent/extensions').with_value('fip_qos,gateway_ip_qos,port_forwarding')
+      end
+    end
   end
 
   shared_examples 'neutron::agents::l3 on Debian' do