This is a Sulawesi hilt. Marine ivory. An unusually upright variant of this form:
http://www.kampungnet.com.sg/modules...view_photo.php
Motif is very very similar to the piece referenced above too. I can only propose that the uprightness is due to limitation in raw material, or to acommodate a very long peksi. Some Sulawesi keris look like they have imported Javanese blades (high quality ones) to me, so could be that the hilt was made to accommodate the long Javanese Peksi. There could be other reasons.