Final answer:
The Kermadec Islands are the northernmost island group in Oceania, located within the Polynesia region and associated with New Zealand.
Step-by-step explanation:
The island group farthest north in Oceania is the Kermadec Islands. These islands are part of the region of Polynesia, which features a number of island groups with large distances between them. The Kermadec Islands are associated with New Zealand, which itself is considered part of the Austral realm. Polynesia spans a vast area in the Pacific, including other island groups such as Hawaii, Easter Island, and the Cook Islands. Despite being geographically isolated, the indigenous peoples of these islands have cultivated rich and diverse cultures with historical sea-faring capabilities that allowed them to traverse the vast oceanic distances.