The tree is Syzygium smithii (previously Acemna smithii); this is an abundant rainforest and moist forest tree throughout the south coast. Fruit colour varies from white to red to purple. Leaf size and and shape is also quite variable.
Has been Syzygium smithii for some years. I go by Australian Plant Census (APC) by Canberra Botanic Gardens. PlantNET (Bot. Gardens Sydney) still has Acemna smithii, but I think it is out of date. Gwen Harden's "Red Book" on rainforest trees in NSW and QLD accepts Syzygium smithii.