Metrosideros diffusa (White Rātā, Climbing Rātā or in Māori Akakura) is a forest liane or vine endemic to New Zealand. It is one of a number of New Zealand Metrosideros species which live out their lives as vines, unlike the northern rata (M.robusta), which generally begins as a hemi-epiphyte and grows into a huge tree. It is part of the subgenus Mearnsia, unlike the main tree species that belong to Metrosideros subspecies Metrosideros.