yes they are more expensive then the NTSC versions, but they're by far not in the top 25 rare games.. they're just "famous" and popular, hence expensive
there are many AUS / NZ only PS1 games and sets that are really rare, the top one offcourse being Grand Theft Auto Double Feature (http://www.playstationcollecting.com...t=2564&p=24724)
as far as I know it's onlly released in Italy and Portugal (I have both these language variants)