Presently, the Australian Government is only considering its options and has not made any formal decisions, so the current age limit of 30 years of age remains in place.
Some key factors that need be considered are timeframes, legal requirements, and most importantly, reciprocity from partner countries for Australian citizens must be in place before the age limit can be raised. If the age limit is raised, it will only be applied to passport holders from countries that have made a reciprocal agreement with Australia.
For more information, please refer to the official Australian Department of Immigration and Border Protection website.