Where can I buy men's bamboo underwear in Vic?

I haven't bought underwear in 11 years. They're all basically just elastic bands at this point. When I go jogging I could put them on my head as a headband, lol. I'd like to invest in some high quality, bamboo underwear because I love the soft, luxurious, silk-like feel of that natural fiber. Please help me find some good underwear. I need them a.s.a.p. so I need a local shop and not an online store.