diff --git a/lib/rake/name_space.rb b/lib/rake/name_space.rb
index 32f8139fc..22ad1f416 100644
--- a/lib/rake/name_space.rb
+++ b/lib/rake/name_space.rb
@@ -21,6 +21,10 @@ def [](name)
     @task_manager.lookup(name, @scope)
   end
 
+  def path
+    @scope.path
+  end
+
   ##
   # The scope of the namespace (a LinkedList)
 
@@ -35,4 +39,20 @@ def tasks
     @task_manager.tasks_in_scope(@scope)
   end
 
+  def namespaces
+    @task_manager.namespaces_in_scope(@scope)
+  end
+
+  def clear
+    namespaces.each do |ns|
+      @task_manager.remove_namespace(ns.path)
+    end
+  end
+
+  class << self
+    def [](namespace_name)
+      Rake.application.lookup_namespace(namespace_name)
+    end
+  end
+
 end
diff --git a/lib/rake/task_manager.rb b/lib/rake/task_manager.rb
index 97e3b9459..9ee718949 100644
--- a/lib/rake/task_manager.rb
+++ b/lib/rake/task_manager.rb
@@ -8,6 +8,7 @@ module TaskManager
 
     def initialize # :nodoc:
       super
+      @namespaces = Hash.new
       @tasks = Hash.new
       @rules = Array.new
       @scope = Scope.make
@@ -50,6 +51,10 @@ def intern(task_class, task_name)
       @tasks[task_name.to_s] ||= task_class.new(task_name, self)
     end
 
+    def remove_task(task_name) # :nodoc:
+      @tasks.delete(task_name)
+    end
+
     # Find a matching task for +task_name+.
     def [](task_name, scopes=nil)
       task_name = task_name.to_s
@@ -178,6 +183,13 @@ def tasks_in_scope(scope)
       }
     end
 
+    def namespaces_in_scope(scope)
+      prefix = scope.path
+      @namespaces.select { |name|
+        name.start_with?(prefix)
+      }.values
+    end
+
     # Clear all tasks in this application.
     def clear
       @tasks.clear
@@ -229,12 +241,24 @@ def in_namespace(name)
       name ||= generate_name
       @scope = Scope.new(name, @scope)
       ns = NameSpace.new(self, @scope)
+      @namespaces[ns.path] = ns
       yield(ns)
       ns
     ensure
       @scope = @scope.tail
     end
 
+    def lookup_namespace(name) # :nodoc:
+      @namespaces[name]
+    end
+
+    def remove_namespace(name) # :nodoc:
+      ns = @namespaces.delete(name)
+      if ns
+        ns.tasks.each { |t| remove_task(t.name) }
+      end
+    end
+
     private
 
     # Add a location to the locations field of the given task.