Great Barrier Island is free of some pests - help keep it this way. Before you visit, check for stowaways that may be harmful to wildlife on this island. Read more about Treasure Islands. Great Barrier is the largest island off the North Island coast. More than 60% of the island is public land administered by the Department of Conservation. There are a range of short walking tracks and longer routes, several campsites, a hut, mountain bike routes, and many natural and historic features to explore. About 850 people live on the island, and there are a number of small settlements with shops and accommodation.