Being a past and likely future permit holder for STILLS photography in Parks managed land (not just National Parks), I am aware of the requirements and costs associated with this sort of photography.
Start here -
http://parks.tas.gov.au/index.aspx?base=924Then have a read of the guidelines.
http://parks.tas.gov.au/index.aspx?base=927For peace of mind to all you photographers out there that submit a photo that ends up for sale in a calendar on this forum (or anywhere else), see this -
3. Stills Photography
Stills photography which is associated with an advertising agency or is for advertising use, will require approval and a fee will be charged (see schedule of fees). All other still photography will not require approval.
I can take any photo I like of nature stuff and sell it anywhere for any cost, no permit required. If I sell that image to an advertising company who are going to use the image to overlay products for sale, a permit WOULD be required.
But if I want to take a photo of a piece of bushwalking related equipment with a view to selling that image for advertising (say to a company), I would need liability insurance, and I would need to go through the registration process on the above link.
That's why some companies out there do not employ photographers to take photos of equipment being used, but rather allow the public to send in their own private images, perhaps for a small reward of credit with that brand if the image is used.
Another scenario, if I took a photo of Cradle Mountain just as a natural photo, I cannot sell that photo to a company that would photoshop or overlay other things over it with a view to advertising.
I've noticed on facebook someone doing Overland Track photography tours. While they may not need a filming permit, I would think that they have the other permits required for running organised tours through the park, or they would be in a lot of trouble. I wonder what liability insurance would cost for such a trip... Their website does say "Our Tours are commercially licensed and supported by Tasmania Parks & Wildlife Services" so all good there.