Australia could not hold up against Chinese invasion(not that that is likely), but its nuclear subs could shut down Chinese exports to North and South America.
The way to rein in China is through trade restrictions and replacing Chinese production with domestic or other Asian country production.
Military blocking of Chinese expansionism is not very practical due to its industrial might and willingness to sustain troop losses.
On the auto parts side, I’m seeing a lot of stuff that used to come out of China is now from Indonesia, Vietnam, or India.