It's the castor oil looper Achaea janata (Erebidae: Erebinae), which despite its name feeds on many other plant hosts including capsicum and other broad-leafed crops (188 records on HOSTS). Here's a link in reference to damage in crops and to garden plants in northern Australia, see also http://lepidoptera.butterflyhouse.com.au/calp/janata.html. It's popped up a few times on PestNet as well.
I often see this on crotons (Codiaeum variegatum) here in Palau. I recall submitting photos to PestNet 10 or 15 years ago. I didn't know that it also ate capsicums.
Yes, Robert Hoare (Lepidopterist at Landcare Research (NZ) agrees. His reply to me was: "I am pretty sure this is Achaea janata, now in family Erebidae. Often associated with castor oil plant, but also feeds on many other plants in various families."
Also, well done to Mani for a nice job mounting the moth for expert ID!
Dear Mani Mua.
The moth looks like Achaea argilla Swinhoe (Lepidoptera: Erebidae) and is native to Australia. It was once A. janata (L.), the castor semi-looper which was widespread from Asia to Australia. It was raised from A. janata to a distinct status by E.D. Edwards. 1978. A review of the genus Achaea Hubner in Australia (Lepidoptera: Noctuidae). Journal of Australian Entomological Society 17: 329-340. The paper is wit keys for adults, male and female genitalia.
So, in Fiji it could be either A. argilla or A. janata.