What is the validity of a divorce that takes place in Australia by complete separation of the spouses for a period of twelve months, after which one of them applies for divorce to the non-Muslim Australian judge?

It is not permissible for Muslims to resort to secular courts. However, if they are compelled to do so in Western countries, they must present their issues to trustworthy Islamic centers that include scholars capable of resolving them. If the grounds for divorce are established, the Islamic body will rule on it, and both parties must accept its judgment. If one party does not accept, the aggrieved party can resubmit the case, and the arbitration body may refer it to the secular court to avert harm. However, if the divorce is by mutual consent of the spouses, there is no impediment to registering it in the secular court, and it will be valid. Both spouses must fear Allah and avoid resorting to Taghut (false deities/tyranny). The husband must exercise his guardianship with kindness and without injustice, and the wife must obey her husband in what is right.