While at the Sir John Guise stadium in Port Moresby, O'Neill thanked organisers and volunteers for their efforts and dismissed the concerns of detractors who said games' venues would not be completed.
"These facilities have been built in record time and now we are seeing them delivered on time," he said.
"Sadly there were negative people who wanted to continually undermine the good work of our games organisers, who made outlandish claims and tried to sour the national sentiment - but they are being proven wrong.
"Of course now is not the time to take a break but to keep working hard and doing your best [because] the finish line is in sight."
Security efforts for the games have been bolstered by Australia's contribution of two Australian Federal Police officers to advise the Royal Papua New Guinea Constabulary's Major Events, Planning and Security Unit.
Although operating in an advisory capacity, the officers will also conduct high-visibility policing at the games venues, with two surveillance balloons supplied by Israel being the ‘eyes in the sky' for security personnel.
The PNG Defence Force have assigned 300 soldiers - who will be serving as special constables and identified with red armbands - to help police during the event.