Some of my favourite writers live in South East Asia. Most of them aren’t as well-known as they should be. I asked Joyce Chng, a Singaporean writer and a friend, if she could help. This gives you somewhere to start. Then you can move on to Victor Ocampo’s lists (to which Joyce gives a link), and keep reading. She says:
Southeast Asia is also home to a small group of established and up-and-coming science fiction and fantasy writers. Believe it or not, we are also writing science fiction for a while now. This is a short list of writers who are either currently residents of the said countries or living in the West.
Singapore
Joyce Chng/J. Damask
J.Y. Yang
Sonny Liew
Isa Kamari
Malaysia
Zen Cho
Nin Harris
Eeleen Lee
Indonesia
Eve Shi
Ernie Kurniawan
Thailand
S. P. Somtow
Vietnam
Aliette de Bodard
Nghi Vo
Hoa Pham
Victor Ocampo has a more detailed list on his website.