O problema foi criado quando você solicitou o ETA, para o qual você não era elegível, como observa que
You must not have any criminal convictions for which you have been sentenced for a total combined period of 12 months or more, whether or not the sentence/s were served.
Agora você terá que solicitar um visto de visitante e pague qualquer taxa aplicável.
O pouco encorajador é que, embora estrito, Estado dos requisitos de entrada da Comunidade da Austrália aquele
You must declare all spent convictions when you complete your application form.
The spent convictions law allows people with minor convictions to disregard those convictions after a certain period of time. A conviction may be considered spent if:
- it is 10 years since the date of the conviction (or five years for juvenile offenders)
- the person was not sentenced to imprisonment or was not sentenced to imprisonment for more than 30 months
- the person has not re-offended during the 10 years (or five years for juveniles) period
The department is allowed to ask you for this information for the purpose of assessing your application.
Como o @pnuts observou, faça-o imediatamente (e com cuidado).