UK visitor staying for 7 weeks. Some travel books say only a passport is required, others say visa or ETA is also required.

I hold a Malaysia passport. I would like to pay a visit to Australia, however, i don’t wish to get stamped in my passport. Can i refused to be stamped since the chip system is available now?
I hold a Malaysia passport. I would like to pay a visit to Australia, however, i don’t wish to get stamped in my passport. Can i refused to be stamped since the chip system is available now? What if i have ETA?