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I know it has been answered here that you can travel as a tourist on a business stream of subclass 600.

Can I travel to Australia as a tourist on a business visitor visa?

But another online source suggested otherwise that the purpose of your trip must be that of the stream you've been granted a visa for.

http://www.australiaforum.com/visas-immigration/58962-holidaying-visitor-fa-600-business-stream-visa.html

Also on my grant, it is stating clearly it is on a "Tourist" stream. So I'm a little worried if I should be applying for another one of a "correct" stream or not. Anyone on a similar situation recently or got any official quote from the Aussie immigration?

Possibly not. You should check the conditions imposed on your visa. These should be listed in your grant notice or you can retrieve it from the VEVO service.

If your visa imposes condition 8101, then you cannot use it for business purposes. Condition 8101 states:

The holder must not engage in work in Australia.

Visas issued under the Business stream would probably have condition 8115 imposed instead of condition 8101. Condition 8115 states (emphasis added):

The holder must not work in Australia other than by engaging in a business visitor activity.

The "business visitor activity" exception is what allows a Visitor visa holder (in the Business stream) to do things related to a business trip.