diff --git a/packages/svelte/src/internal/client/runtime.js b/packages/svelte/src/internal/client/runtime.js
index 2375dc0a63..d790c0ad14 100644
--- a/packages/svelte/src/internal/client/runtime.js
+++ b/packages/svelte/src/internal/client/runtime.js
@@ -828,15 +828,16 @@ 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);
 }
 
 /**