My Australian student visa was declined in March 2016. After that I applied for a New Zealand student visa in june 2016 and it was also declined.
What can I do now? Can I reapply again in both countries?
Yes, you can reapply, but unless your new applications are significantly different, you will be refused again.
You need to figure out why your applications were refused. If you were refused because your circumstances do not allow you to qualify as a student, then you should not reapply until your circumstances change. If you were refused because deficiencies in the application caused it not to represent your circumstances accurately, then you should identify and correct those deficiencies before reapplying.