So i check the building company(ies)... : CPB (owned by CIMIC - which used to be Australian but it's not now coz it is owned by Hochtief (Germany)- which is owned by ACS group a Spanish construction giant).

Their partner in the project is John Holland.

John Holland is a famous Australian name. Started the company in 1949, built it into a major international player. That’s good going for one lifetime.

Coincidentally, one of his biggest breaks was winning the contract to build the West Gate Bridge in 1968. The West Gate tunnel, 50 years later, will be the company’s second crossing.

An Aside: The West Gate Bridge did famously collapse 50 years ago during construction. When it came to joining up the bridge in the middle, the engineers realized one side was 11 cm higher than the other. They thought the high side could be forced down by placing “10 massive concrete blocks” on it with a combined weight of 80 tonnes.

“The process caused a buckle in the bridge, which engineers tried to fix by removing a number of bolts.”

Around midday, worker Pat Preston “ heard what he thought was the crackling of gunfire, but was actually the sound of bolts pinging from the frame of the bridge.”

35 workers were killed in the ensuing, thunderous collapse.

Hopefully safety measures have been put in place since then. Didn’t seem to affect business too much because a decade later they won the new Parliament House gig. That hasn't fallen down yet.

As for the China connection ‘conspiracy theory?’ So far, on the face of it, the whole project looks Aussie through-and-through! (With some Spanish in there)

Good thing we know that things in the global corporate-politico-science world are often not what they seem. ..