M'thinks Noffke's just not rated as highly by the Aussie camp as others are. Bowls largely straight up-and-down fast-meds and I believe there are questions about his ability under pressure and whether, in taking the step up to international level, whether he'd suddenly lose his radar. It's why he had to get his batting up to get noticed.
It's part of why Bichel got ignored for so long. The perception was that playing half his games at the Gabba made him look a better bowler than he really was and when he actually was picked for Australia, it's hard to argue against that as he rarely looked like he was about to absolutely run through a side (7-fer against England in 2003 excepted where, for a 5 over spell, he was simply awesome). Kasper suffered a similar perception but to a lesser extent, probably helped by his bowling on an early tour to India. Noffke, I'd be surprised if the Gabba argument didn't come up when his name is bandied about the selection table.