According to today's news, most of the venues are already in place at the Gold Coast (which is part of the reason why it won the bid) - so I can't see there being the need for a huge amount of construction workers to come. There will definitely be some construction, but we aren' talking about massive amounts of construction.
"Coffa said the Gold Coast, with the bulk of its venues already in place, could be trusted to hold a successful event in April 2018.