澳大利亚600被拒……可以申诉或者复议吗？？？？

大伯和伯母申请600被拒，大家帮忙看一下这种情况的如何申诉或者复议的？因为挺着急的，二老着急去看我哥，我哥现在正在决定是要回国还是要留在澳大利亚，需要二老帮忙参考一下。
下附拒签原因
you stated in your application that you intend to visit australia for tourisum.you have not demonstrated sufficient commitments in China as an incentive for your retern. More specifically, Inote that you have provided some evidence of your financial standing, though the amounts noted could not be considered significant in the context of this assessment for your return from travel to Australia.
他俩申请的而是旅游为目的，因为据说旅游比较好签，但实质上是想去看我哥，从头至尾没收到任何电话调查，两人是自己经营商行的，现在的商行做了5年，商行的电话也没有接到任何消息。跟旅游目的有没有关系？求大神帮忙出个招，要是能复议或申诉是最好的……
请求大神支招，急的火急火燎啊……{:2_50:}