tourist visa into australia

hi everyone in new to this site but i seem to have a problem maybe someone can help me with,

my sister wants to bring a friend from turkey to australia for a visit and we had sent a form from australia sponsoring and accepting the friend that she has a place to stay with us, now my sister didnt apply to the immigration office yet, due to waiting on the letter only to find out its been 2 weeks and no letter has arrived and it is now lost. they are scheduled to come on the 17th of january, how long will it take them to get a visa and if there is any faster methods?

You should refer to the information on the Australian Department of Immigration Website for details about visas and routine processing time. If you are concerned about whether the visa will be processed in time, contact the Department directly. Contact details are on the webiste and vary depending on which visa your sister and her friend have applied for.