diff --git a/packages/svelte/src/internal/client/runtime.js b/packages/svelte/src/internal/client/runtime.js
index 87a69cb851..4c6996db39 100644
--- a/packages/svelte/src/internal/client/runtime.js
+++ b/packages/svelte/src/internal/client/runtime.js
@@ -833,15 +833,16 @@ export function flushSync(fn) {
 			result = fn();
 		}
 
-		flush_tasks();
+		while (true) {
+			flush_tasks();
+
+			if (queued_root_effects.length === 0) {
+				return /** @type {T} */ (result);
+			}
 
-		while (queued_root_effects.length > 0) {
 			is_flushing = true;
 			flush_queued_root_effects();
-			flush_tasks();
 		}
-
-		return /** @type {T} */ (result);
 	} finally {
 		is_flushing_sync = previously_flushing_sync;
 	}