diff --git a/lib/moddle.js b/lib/moddle.js
index 64bfd47..0b27fa6 100644
--- a/lib/moddle.js
+++ b/lib/moddle.js
@@ -35,8 +35,10 @@ import {
  * var moddle = new Moddle([pkg]);
  *
  * @param {Array<Package>} packages the packages to contain
+ *
+ * @param { { strict?: boolean } } [config] moddle configuration
  */
-export default function Moddle(packages) {
+export default function Moddle(packages, config = {}) {
 
   this.properties = new Properties(this);
 
@@ -44,6 +46,8 @@ export default function Moddle(packages) {
   this.registry = new Registry(packages, this.properties);
 
   this.typeCache = {};
+
+  this.config = config;
 }
 
 
diff --git a/lib/properties.js b/lib/properties.js
index 513a0b1..f57e8c4 100644
--- a/lib/properties.js
+++ b/lib/properties.js
@@ -27,7 +27,7 @@ Properties.prototype.set = function(target, name, value) {
     throw new TypeError('property name must be a non-empty string');
   }
 
-  var property = this.model.getPropertyDescriptor(target, name);
+  var property = this.getProperty(target, name);
 
   var propertyName = property && property.name;
 
@@ -38,7 +38,7 @@ Properties.prototype.set = function(target, name, value) {
     if (property) {
       delete target[propertyName];
     } else {
-      delete target.$attrs[name];
+      delete target.$attrs[stripGlobal(name)];
     }
   } else {
 
@@ -51,7 +51,7 @@ Properties.prototype.set = function(target, name, value) {
         defineProperty(target, property, value);
       }
     } else {
-      target.$attrs[name] = value;
+      target.$attrs[stripGlobal(name)] = value;
     }
   }
 };
@@ -66,10 +66,10 @@ Properties.prototype.set = function(target, name, value) {
  */
 Properties.prototype.get = function(target, name) {
 
-  var property = this.model.getPropertyDescriptor(target, name);
+  var property = this.getProperty(target, name);
 
   if (!property) {
-    return target.$attrs[name];
+    return target.$attrs[stripGlobal(name)];
   }
 
   var propertyName = property.name;
@@ -123,6 +123,44 @@ Properties.prototype.defineModel = function(target, model) {
   this.define(target, '$model', { value: model });
 };
 
+/**
+ * Return property with the given name on the element.
+ *
+ * @param {any} target
+ * @param {string} name
+ *
+ * @return {object | null} property
+ */
+Properties.prototype.getProperty = function(target, name) {
+
+  var model = this.model;
+
+  var property = model.getPropertyDescriptor(target, name);
+
+  if (property) {
+    return property;
+  }
+
+  if (name.includes(':')) {
+    return null;
+  }
+
+  const strict = model.config.strict;
+
+  if (typeof strict !== 'undefined') {
+    const error = new TypeError(`unknown property <${ name }> on <${ target.$type }>`);
+
+    if (strict) {
+      throw error;
+    } else {
+
+      // eslint-disable-next-line no-undef
+      typeof console !== 'undefined' && console.warn(error);
+    }
+  }
+
+  return null;
+};
 
 function isUndefined(val) {
   return typeof val === 'undefined';
@@ -135,4 +173,8 @@ function defineProperty(target, property, value) {
     value: value,
     configurable: true
   });
+}
+
+function stripGlobal(name) {
+  return name.replace(/^:/, '');
 }
\ No newline at end of file
diff --git a/test/helper.js b/test/helper.js
index 7056f89..550a6d1 100644
--- a/test/helper.js
+++ b/test/helper.js
@@ -21,7 +21,7 @@ export function createModelBuilder(base) {
     throw new Error('[test-util] must specify a base directory');
   }
 
-  function createModel(packageNames) {
+  function createModel(packageNames, config = {}) {
 
     var packages = map(packageNames, function(f) {
       var pkg = cache[f];
@@ -38,7 +38,7 @@ export function createModelBuilder(base) {
       return pkg;
     });
 
-    return new Moddle(packages);
+    return new Moddle(packages, config);
   }
 
   return createModel;
diff --git a/test/spec/moddle.js b/test/spec/moddle.js
index 63e53cf..b80f55b 100644
--- a/test/spec/moddle.js
+++ b/test/spec/moddle.js
@@ -356,6 +356,38 @@ describe('moddle', function() {
         expect(element.get('props:count')).to.eql(10);
       });
 
+
+      it('should access global name', function() {
+
+        // when
+        const element = moddle.create('props:ComplexCount', {
+          ':xmlns': 'http://foo'
+        });
+
+        // then
+        expect(element.get(':xmlns')).to.eql('http://foo');
+        expect(element.get('xmlns')).to.eql('http://foo');
+
+        // available as extension attribute
+        expect(element.$attrs).to.have.property('xmlns');
+      });
+
+
+      it('should access global name (no prefix)', function() {
+
+        // when
+        const element = moddle.create('props:ComplexCount', {
+          'xmlns': 'http://foo'
+        });
+
+        // then
+        expect(element.get(':xmlns')).to.eql('http://foo');
+        expect(element.get('xmlns')).to.eql('http://foo');
+
+        // available as extension attribute
+        expect(element.$attrs).to.have.property('xmlns');
+      });
+
     });
 
 
@@ -376,4 +408,115 @@ describe('moddle', function() {
 
   });
 
+
+  describe('property access (lax)', function() {
+
+    const moddle = createModel([
+      'properties'
+    ], {
+      strict: false
+    });
+
+
+    describe('typed', function() {
+
+      it('should access unknown attribute', function() {
+
+        // when
+        const element = moddle.create('props:ComplexCount', {
+          foo: 'bar'
+        });
+
+        // then
+        expect(element.get('foo')).to.eql('bar');
+      });
+
+    });
+
+  });
+
+
+  describe('property access (strict)', function() {
+
+    const moddle = createModel([
+      'properties'
+    ], {
+      strict: true
+    });
+
+
+    it('should configure in strict mode', function() {
+
+      // then
+      expect(moddle.config.strict).to.be.true;
+    });
+
+
+    describe('typed', function() {
+
+      it('should access basic', function() {
+
+        // when
+        const element = moddle.create('props:ComplexCount', {
+          count: 10
+        });
+
+        // then
+        expect(element.get('count')).to.eql(10);
+        expect(element.get('props:count')).to.eql(10);
+
+        // available under base name
+        expect(element.count).to.exist;
+      });
+
+
+      it('should access global name', function() {
+
+        // when
+        const element = moddle.create('props:ComplexCount', {
+          ':xmlns': 'http://foo'
+        });
+
+        // then
+        expect(element.get(':xmlns')).to.eql('http://foo');
+
+        expect(() => {
+          element.get('xmlns');
+        }).to.throw(/unknown property <xmlns> on <props:ComplexCount>/);
+
+        // available as extension attribute
+        expect(element.$attrs).to.have.property('xmlns');
+      });
+
+
+      it('fail accessing unknown property', function() {
+
+        // when
+        const element = moddle.create('props:ComplexCount');
+
+        // then
+        expect(() => {
+          element.get('foo');
+        }).to.throw(/unknown property <foo> on <props:ComplexCount>/);
+
+        expect(() => {
+          element.set('foo', 10);
+        }).to.throw(/unknown property <foo> on <props:ComplexCount>/);
+      });
+
+
+      it('fail instantiating with unknown property', function() {
+
+        // then
+        expect(() => {
+          moddle.create('props:ComplexCount', {
+            foo: 10
+          });
+        }).to.throw(/unknown property <foo> on <props:ComplexCount>/);
+      });
+
+    });
+
+  });
+
 });