A 489 regional sponsored visa is given to a candidate and as per it; he gets the right to be in Australia for 4 years in a region which does not have a sufficient population growth.
There are three streams as per which anyone can get a visa:
Extended stay pathway: As per this stream, there are certain threshold conditions which apply to you:
The candidate must be having one of the visas out of the following for 2 years:
475 visa which is Employer Sponsorship Visa for 4 years
487 visa which is the Skilled Regional Sponsored Visa
495 visa which is the Independent Regional Visa
496 visa which is Designated Area Sponsored Provisional Visa
None of the above visas are valid now, however, candidates who have been living in Australia as per the conditions eligible for these visas for 2 years can get the 489 visa.
Invited pathway: This visa can be given to those who have already the invitation from a relative who is residing in an Australian region. Apart from that, you have to provide the Expression Of Interest which should indicate that you have scored the 60 points. So, after the invitation from the relative and your application, once the DIBP selects you can then proceed to make the concerned application for the 489 visa. So, if a relative has nominated you, in whichever state he lives, you have to live in the same state in an area with scarce population growth.
The other way for you to get this visa is to provide an Expression Of Interest with a point score of 60 and get an invitation from a specific state or provincial government. Whichever state has nominated you, you must reside in a region which has an inadequate population growth, in the same state.
Subsequent entry pathway: This visa application allows one to add a family member for the 489 visa application. And, this relative can be your partner in a live-in relationship with you or your wife. You can also nominate a child, who is less than 18 or more than 18 but less than 23. He can be more than 23 if he is not having the ability to take financially take care of himself due to, some kind of issues. Now, whosoever is nominating the relative for the 489 visa should be already having the 489 visa with himself. Other visas which make you eligible for providing someone with the sponsorship for the 489 visa are 475, 496, 495 or the 487 visas.
The sponsored relative must have the score of 4.5 in all the parts of IELTS(Functional English). Whatever tests you have taken to prove this, level of English language expertise should be only 1 year old at the time of application.
There is no requirement for this test, once you are ready to pay supplementary fees for this visa.
So, now the question is why the DIBP is taking such a long time to provide one with this visa is because the processing time varies with the stream you are using for this visa grant. You eventually need 5 months for this visa to be granted.