In the curtain raiser Niue beat Solomon Islands 19-17.
The Niueans making their return to international XV's after an eight year absence.
In the later match the hosts Papua New Guinea beat Nauru 89-7.
For Nauru it was their first ever international 15 a side rugby game.
The next round of the competition on Tuesday will see Solomon Islands taking on Nauru and PNG playing Niue.