Having worked in construction in places like Darwin which has a...

Having worked in construction in places like Darwin which has a similar wet season I can confirm that construction continues during wet seasons. Concrete won't be poured in heavy very rain periods but there would be plenty of opportunity to pour. In fact once concrete is poured having water sprayed over it a few hours later and over the next few days prevents the concrete from cracking and makes it a much cleaner finish. So in my eyes this won't affect starting construction.
Civil construction may be slowed down if torrential rain falls as de-watering takes extra time pumping out water if that's required.
Heavy rain would affect the plant install but that should be closer to the dry season by the time it starts. Electrical works obviously likes to dry, but by this stage roofs of the shed etc would already be up providing dry environment. A quick google says around 130-160mm of rain can be expected per month during the wet season. East coast of Australia has had rain fall events of 100mm in a day this year at various times and I don't see any construction jobs not starting because of it or even stopping for more then a few days.
Just my thoughts