Although my PC timezone is set to +10:00 I get the following...
$asctime(z) returns +11
$timezone returns -39600
$calc($timezone / 3600) returns -11
$calc(($ctime - $gmt) / 3600) returns 11
Are you saying your computer is set to not observe DST? According to your location your current offset from GMT should be +11 (AEDT), not +10 (AEST).