If the Chinese wanted to invade Australia they could have done so any time within the last decade without breaking a sweat.
The conspiracy theory is amusing and the voters in WA at least have largely switched off to UAP's claims and mock Clive Palmer.
Actually they cant - they dont have a blue water navy - force projection requires a blue water navy that can sustain itself and a couple of aircraft carriers at sea for extended periods or your expensive expedition will lie at the bottom of the ocean.
Make no mistake the chinese are developing this capability - but they dont currently have the ability to force project much past their own region.
They have one functioning aircraft carrier - a refitted old soviet carrier and own a couple of others for study purposes (including hmas melbourne) and one in completion
The one they have is small in comparison to a yank carrier carrying 48 aircraft designed more for ground support- their second one will have a few more.
Any invasion force would have the carriers targeted and sunk expeditiously by sub or aircraft - then all you have is a big mass of targets - essentially defenceless without a carrier.
Any serious force projection would require a bunch of carriers - with several specialising in interdiction.
By the time they have that we will have the jsf - which despite the bad press will be basically clubbing baby harp seals when matched against the chinese development of the sukhoi.