Pine needles are acid based, not alkaline. But not strongly so. Usually, it is not the needles that prevent or smother growth, rather, it is the pine tree roots underneath the fallen needles that steal the available nutrients and especially water. This effectively deters a lot of plant growth in that area. I am sure there are plants that are adapted to such conditions in your part of Australia, but I wouldn't have a clue which, since I am from the northern U.S.A.

Bogs where carnivorous plants grow are naturally very, very acidic. Pine needles are a good mulch for protection in winter that will not change the pH (acidity) of the bog. That's a good thing.