This study surveys liana communities at 26 sites across undisturbed and disturbed forests from 70 to 2,700 m above sea level in northern parts of Papua New Guinea (PNG). The assessment was conducted following the Papua New Guinea National Forest Inventory (NFI) manual. The results show a total diversity of 68 genera of lianas, belonging to 33 families. No significant difference was observed in abundance of liana species between lowland unlogged (i.e., primary and pristine) and logged (disturbed) forests and lower montane unlogged forests. Richness is not significantly different between lowland and montane sites, as opposed to outcomes in other studies which have often reported a decrease in species richness with elevation. Both types of lowland forests do not show indicator genera, while the unlogged montane forests are characterized by Rubus and Sabia genera. The study shows a high taxonomic richness of lianas in PNG, supporting previous research and underlining that they make a significant contribution to the overall woody species richness and to the ecology and complexity of PNG forest.