This is Macaria abydata
Geometridae, Ennominae, Macariini
A common and widespread species in Hong Kong, but not native, - "The species-group includes the Neotropical species abydata Guenée, which has spread, via Hawaii, to the SW Pacific, Indonesia, Malaysia (Holloway, : 161) probably with one of its foodplants, Leucaena." (Scoble & Krüger, 2003: 295).
Holloway, J.D., 1994 (dated 1993). The Moths of Borneo: family Geometridae, subfamily Ennominae; part 11. Malayan Nature Journal 47: 1–309. [593 figs, 19 col. pls.]
Scoble, M.J. & Krüger, M., 2003. A review of the genera of Macariini with a revised classification of the tribe (Geometridae: Ennominae). Zoological Journal of the Linnean Society 134: 257–315.