The side beat Tahiti 2-1 at the HFC Stadium in Suva, Sunday.
Ramona Padio’s first-half penalty put PNG in the lead just before the break.
Meagen Gunemba’s second-half breakaway finish ensured PNG advanced as group winners.
Tahiti pulled one back with a penalty to Tahia Tamarii to end the game at 2-1.
The final game in Group B takes place on Wednesday when Tahiti face Vanuatu with both teams hunting for a positive result to ensure safe passage into the last eight.