Hi @Malini,
Thank you for your question and welcome to the Bunnings Workshop community, it is fantastic to have you with us.
Bunnings did sell them in the past but unfortunately it looks like they are no longer stocked.
A similar alternative is the Tumbleweed Worm Buffet In Ground Worm Farm, however it does not break down over time.
You could also make your own out of packing tubes or pvc pipe, by simply drilling a number of holes using spade bits.
Let me know what you think and if you have any further questions, please don't hesitate to ask.
Jacob
