Hello dear student,

You might get admission in colleges in Australia on the basis of your class 12th as you have passed it. You can try for the graduation degree but for which so ever  University you are going to apply kindly check the eligibility criteria so that it doesn't trouble you in later stage . As every University have their own eligibility criteria.

Best wishes

If you have discontinued your B.Tech, your highest qualification will remain 12th. And you can apply to Undergraduation courses based on your 12th qualification. The process will be the same like appear for any relevant Language Proficiency test and apply for Universities. Your discontinuation of studies will have nothing to do with you planning on pursuing your Undergraduation abroad. But your statements of purpose and other documents should be a solid proof that you are serious about what you want to pursue in that Country.