She can only really look at getting a visitor visa, perhaps going for a six month one to hopefully allow enough time for the visa to be processed.
There is some risk attached in that your wife needs to be outside of Australia for the visa to be granted and though that can be done easily enough by a flight to NZ or elsewhere, it is not official policy that Immi have the responsibility to check where people are and advise them they need to leave Australia, thoughg that has happened in a number of instances I know of.
Regardless, the onus will be with the applicant and if for whatever reason, a change of staff for instance and the visa is presented for granting and the system rejects it because the computer indicates the person is in Australia, I am not too sure whether the system can take a backward step as bureaucratic as it may seem.
You may want to check with the Immi people in SA to see whether they actually have something in place locally to facilitate a check/advise/travel scenario and perhaps submitting a Form 1022 to have a greater chance of recognition could be appropriate.
If you do decide to go for a visitor visa, they do not allow for working though you can apply to have that restriction lifted and that will be decided on application.