diff --git a/packages/block-editor/src/hooks/child-layout.js b/packages/block-editor/src/hooks/child-layout.js
index b530411c884ff..bf216f3299554 100644
--- a/packages/block-editor/src/hooks/child-layout.js
+++ b/packages/block-editor/src/hooks/child-layout.js
@@ -135,9 +135,13 @@ export function hasChildLayoutSupport( {
 } ) {
 	const {
 		type: parentLayoutType = 'default',
+		default: { type: defaultParentLayoutType = 'default' } = {},
 		allowSizingOnChildren = false,
 	} = parentLayout;
-	const support = parentLayoutType === 'flex' && allowSizingOnChildren;
+
+	const support =
+		( defaultParentLayoutType === 'flex' || parentLayoutType === 'flex' ) &&
+		allowSizingOnChildren;
 
 	return support;
 }
diff --git a/packages/block-library/src/navigation/block.json b/packages/block-library/src/navigation/block.json
index b54da128bd86e..ee67381620149 100644
--- a/packages/block-library/src/navigation/block.json
+++ b/packages/block-library/src/navigation/block.json
@@ -119,6 +119,7 @@
 			"allowSwitching": false,
 			"allowInheriting": false,
 			"allowVerticalAlignment": false,
+			"allowSizingOnChildren": true,
 			"default": {
 				"type": "flex"
 			}