diff --git a/compiler/parser.pas b/compiler/parser.pas
index eee5fd7e75..05461808eb 100644
--- a/compiler/parser.pas
+++ b/compiler/parser.pas
@@ -202,7 +202,7 @@ implementation
            system_wasm32_wasi:
              begin
                if ts_wasm_threads in init_settings.targetswitches then
-                 maxheapsize:=33554432
+                 maxheapsize:=268435456
                else
                  maxheapsize:=0;
              end;