diff --git a/rosidl_runtime_py/rosidl_runtime_py/__init__.py b/rosidl_runtime_py/rosidl_runtime_py/__init__.py
index 5f40b2ed..a047d61c 100644
--- a/rosidl_runtime_py/rosidl_runtime_py/__init__.py
+++ b/rosidl_runtime_py/rosidl_runtime_py/__init__.py
@@ -15,10 +15,12 @@
 from .convert import message_to_csv
 from .convert import message_to_ordereddict
 from .convert import message_to_yaml
+from .import_message import import_message_type
 from .set_message import set_message_fields
 
 
 __all__ = [
+    'import_message_type',
     'message_to_csv',
     'message_to_ordereddict',
     'message_to_yaml',
diff --git a/rosidl_runtime_py/rosidl_runtime_py/import_message.py b/rosidl_runtime_py/rosidl_runtime_py/import_message.py
new file mode 100644
index 00000000..24e97b7b
--- /dev/null
+++ b/rosidl_runtime_py/rosidl_runtime_py/import_message.py
@@ -0,0 +1,33 @@
+# Copyright 2017-2019 Open Source Robotics Foundation, Inc.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+import importlib
+
+
+def import_message_type(topic_name: str, message_type: str):
+    # TODO(dirk-thomas) this logic should come from a rosidl related package
+    try:
+        package_name, message_name = message_type.split('/', 2)
+        if not package_name or not message_name:
+            raise ValueError()
+    except ValueError:
+        raise RuntimeError('The passed message type is invalid')
+
+    # TODO(sloretz) node API to get topic types should indicate if action or msg
+    middle_module = 'msg'
+    if topic_name.endswith('/_action/feedback'):
+        middle_module = 'action'
+
+    module = importlib.import_module(package_name + '.' + middle_module)
+    return getattr(module, message_name)
diff --git a/rosidl_runtime_py/rosidl_runtime_py/set_message.py b/rosidl_runtime_py/rosidl_runtime_py/set_message.py
index cfb36563..91b372d1 100644
--- a/rosidl_runtime_py/rosidl_runtime_py/set_message.py
+++ b/rosidl_runtime_py/rosidl_runtime_py/set_message.py
@@ -15,6 +15,8 @@
 from typing import Any
 from typing import Dict
 
+from rosidl_runtime_py.import_message import import_message_type
+
 
 def set_message_fields(msg: Any, values: Dict[str, str]) -> None:
     """
@@ -33,4 +35,17 @@ def set_message_fields(msg: Any, values: Dict[str, str]) -> None:
         except TypeError:
             value = field_type()
             set_message_fields(value, field_value)
+        f_type = msg.get_fields_and_field_types()[field_name]
+        # Check if field is an array of ROS message types
+        if f_type.find('/') != -1:
+            if isinstance(field_type(), list):
+                # strip the 'sequence<' prefix if it is a sequence
+                if f_type.startswith('sequence'):
+                    f_type = f_type[len('sequence') + 1:]
+                f_type = f_type[:f_type.rfind('[')]
+                field_elem_type = import_message_type('', f_type)
+                for n in range(len(value)):
+                    submsg = field_elem_type()
+                    set_message_fields(submsg, value[n])
+                    value[n] = submsg
         setattr(msg, field_name, value)
diff --git a/rosidl_runtime_py/test/rosidl_runtime_py/test_set_message.py b/rosidl_runtime_py/test/rosidl_runtime_py/test_set_message.py
index a74a6d92..4f178d65 100644
--- a/rosidl_runtime_py/test/rosidl_runtime_py/test_set_message.py
+++ b/rosidl_runtime_py/test/rosidl_runtime_py/test_set_message.py
@@ -91,3 +91,39 @@ def test_set_message_fields_invalid():
     invalid_type['int32_value'] = 'this is not an integer'
     with pytest.raises(ValueError):
         set_message_fields(msg, invalid_type)
+
+
+def test_set_nested_namespaced_fields():
+    unbounded_sequence_msg = message_fixtures.get_msg_unbounded_sequences()[1]
+    test_values = {
+        'basic_types_values': [
+            {'float64_value': 42.42, 'int8_value': 42},
+            {'float64_value': 11.11, 'int8_value': 11}
+        ]
+    }
+    set_message_fields(unbounded_sequence_msg, test_values)
+    assert unbounded_sequence_msg.basic_types_values[0].float64_value == 42.42
+    assert unbounded_sequence_msg.basic_types_values[0].int8_value == 42
+    assert unbounded_sequence_msg.basic_types_values[0].uint8_value == 0
+    assert unbounded_sequence_msg.basic_types_values[1].float64_value == 11.11
+    assert unbounded_sequence_msg.basic_types_values[1].int8_value == 11
+    assert unbounded_sequence_msg.basic_types_values[1].uint8_value == 0
+
+    arrays_msg = message_fixtures.get_msg_arrays()[0]
+    test_values = {
+        'basic_types_values': [
+            {'float64_value': 42.42, 'int8_value': 42},
+            {'float64_value': 11.11, 'int8_value': 11},
+            {'float64_value': 22.22, 'int8_value': 22},
+        ]
+    }
+    set_message_fields(arrays_msg, test_values)
+    assert arrays_msg.basic_types_values[0].float64_value == 42.42
+    assert arrays_msg.basic_types_values[0].int8_value == 42
+    assert arrays_msg.basic_types_values[0].uint8_value == 0
+    assert arrays_msg.basic_types_values[1].float64_value == 11.11
+    assert arrays_msg.basic_types_values[1].int8_value == 11
+    assert arrays_msg.basic_types_values[1].uint8_value == 0
+    assert arrays_msg.basic_types_values[2].float64_value == 22.22
+    assert arrays_msg.basic_types_values[2].int8_value == 22
+    assert arrays_msg.basic_types_values[2].uint8_value == 0