Is it permissible to have an 'urfi marriage in Australia in pursuit of chastity and stability?

If all the conditions for marriage are met in an urfi marriage (customary marriage), then it is permissible and valid in Islamic law. It is not harmed by the fact that it is not registered in courts. The conditions for the validity of marriage are: the woman's guardian (wali), the dowry (sadaq) as stated in the Almighty's saying: "And give women their dowries as a free gift," the صيغة (ijab and qabul - offer and acceptance), and two witnesses, based on the Prophet's (peace be upon him) saying: "There is no marriage except with a guardian and two witnesses."