What is the maximum number of witnesses for a wedding

Hi everyone! My fiance and I are French from birth but are now both recently Australian citizens. In countries like France or the UK you can have up to 6 witnesses (aged over 18 years old obviously) to be witnesses at your wedding. We were wondering if 2 is the max here in Western Australia or if it is the minimum number. If 2 is the minimum for the number of witnesses what would be the maximum number?