diff --git a/spring-webflux/src/main/kotlin/org/springframework/web/reactive/function/server/CoRouterFunctionDsl.kt b/spring-webflux/src/main/kotlin/org/springframework/web/reactive/function/server/CoRouterFunctionDsl.kt
index 3a861daf9d..5beed8e41c 100644
--- a/spring-webflux/src/main/kotlin/org/springframework/web/reactive/function/server/CoRouterFunctionDsl.kt
+++ b/spring-webflux/src/main/kotlin/org/springframework/web/reactive/function/server/CoRouterFunctionDsl.kt
@@ -26,13 +26,22 @@ import org.springframework.http.MediaType
 import org.springframework.web.reactive.function.server.RouterFunctions.nest
 import java.net.URI
 
+/**
+ * Coroutines variant of [router].
+ *
+ * @author Sebastien Deleuze
+ * @since 5.2
+ */
+fun coRouter(routes: (CoRouterFunctionDsl.() -> Unit)) =
+        CoRouterFunctionDsl(routes).build()
+
 /**
  * Coroutines variant of [RouterFunctionDsl].
  *
  * @author Sebastien Deleuze
  * @since 5.2
  */
-open class CoRouterFunctionDsl(private val init: (CoRouterFunctionDsl.() -> Unit)): () -> RouterFunction<ServerResponse> {
+class CoRouterFunctionDsl(private val init: (CoRouterFunctionDsl.() -> Unit)) {
 
     private val builder = RouterFunctions.route()
 
@@ -104,7 +113,7 @@ open class CoRouterFunctionDsl(private val init: (CoRouterFunctionDsl.() -> Unit
      * @see RouterFunctions.nest
      */
     fun RequestPredicate.nest(r: (CoRouterFunctionDsl.() -> Unit)) {
-        builder.add(nest(this, CoRouterFunctionDsl(r).invoke()))
+        builder.add(nest(this, CoRouterFunctionDsl(r).build()))
     }
 
 
@@ -396,10 +405,10 @@ open class CoRouterFunctionDsl(private val init: (CoRouterFunctionDsl.() -> Unit
         }
     }
 
-	/**
-	 * Return a composed routing function created from all the registered routes.
-	 */
-    override fun invoke(): RouterFunction<ServerResponse> {
+    /**
+     * Return a composed routing function created from all the registered routes.
+     */
+    internal fun build(): RouterFunction<ServerResponse> {
         init()
         return builder.build()
     }
@@ -484,12 +493,3 @@ open class CoRouterFunctionDsl(private val init: (CoRouterFunctionDsl.() -> Unit
  */
 operator fun <T: ServerResponse> RouterFunction<T>.plus(other: RouterFunction<T>) =
         this.and(other)
-
-/**
- * Coroutines variant of [router].
- *
- * @author Sebastien Deleuze
- * @since 5.2
- */
-fun coRouter(routes: (CoRouterFunctionDsl.() -> Unit)) =
-        CoRouterFunctionDsl(routes).invoke()
\ No newline at end of file
diff --git a/spring-webflux/src/main/kotlin/org/springframework/web/reactive/function/server/RouterFunctionDsl.kt b/spring-webflux/src/main/kotlin/org/springframework/web/reactive/function/server/RouterFunctionDsl.kt
index f2b5b7ba66..e85715c010 100644
--- a/spring-webflux/src/main/kotlin/org/springframework/web/reactive/function/server/RouterFunctionDsl.kt
+++ b/spring-webflux/src/main/kotlin/org/springframework/web/reactive/function/server/RouterFunctionDsl.kt
@@ -26,8 +26,8 @@ import java.net.URI
 import java.util.function.Supplier
 
 /**
- * Allow to create easily a `RouterFunction<ServerResponse>` from a Kotlin router DSL based
- * on the same building blocks as the Java one ([RouterFunction], [RequestPredicate],
+ * Allow to create easily a WebFlux.fn `RouterFunction<ServerResponse>` from a Kotlin
+ * router DSL leveraging WebFlux.fn Java API ([RouterFunction], [RequestPredicate],
  * [HandlerFunction]).
  *
  * Example:
@@ -55,7 +55,7 @@ import java.util.function.Supplier
  * @see RouterFunctions.Builder
  * @since 5.0
  */
-fun router(routes: RouterFunctionDsl.() -> Unit) = RouterFunctionDsl(routes).invoke()
+fun router(routes: RouterFunctionDsl.() -> Unit) = RouterFunctionDsl(routes).build()
 
 /**
  * Provide a [RouterFunction] Kotlin DSL in order to be able to write idiomatic Kotlin code.
@@ -64,7 +64,7 @@ fun router(routes: RouterFunctionDsl.() -> Unit) = RouterFunctionDsl(routes).inv
  * @author Yevhenii Melnyk
  * @since 5.0
  */
-open class RouterFunctionDsl(private val init: RouterFunctionDsl.() -> Unit) : () -> RouterFunction<ServerResponse> {
+class RouterFunctionDsl(private val init: RouterFunctionDsl.() -> Unit) {
 
 	private val builder = RouterFunctions.route()
 
@@ -136,7 +136,7 @@ open class RouterFunctionDsl(private val init: RouterFunctionDsl.() -> Unit) : (
 	 * @see RouterFunctions.nest
 	 */
 	fun RequestPredicate.nest(init: RouterFunctionDsl.() -> Unit) {
-		builder.nest(this, Supplier { RouterFunctionDsl(init).invoke() })
+		builder.nest(this, Supplier { RouterFunctionDsl(init).build() })
 	}
 
 	/**
@@ -148,7 +148,7 @@ open class RouterFunctionDsl(private val init: RouterFunctionDsl.() -> Unit) : (
 	 * @see RequestPredicates.path
 	*/
 	fun String.nest(init: RouterFunctionDsl.() -> Unit) {
-		builder.path(this, Supplier { RouterFunctionDsl(init).invoke() })
+		builder.path(this, Supplier { RouterFunctionDsl(init).build() })
 	}
 
 	/**
@@ -545,7 +545,7 @@ open class RouterFunctionDsl(private val init: RouterFunctionDsl.() -> Unit) : (
 	 * Return a composed routing function created from all the registered routes.
 	 * @since 5.1
 	 */
-	override fun invoke(): RouterFunction<ServerResponse> {
+	internal fun build(): RouterFunction<ServerResponse> {
 		init()
 		return builder.build()
 	}