A new PHP conference has been announced as the "first pan-asian PHP conference": PHP Conference Asia. While the details are a bit sparse right now, they do have a form on the main site where you can enter your details for more information.
The conference will be held in Singapore in September (24th and 25th). The call for papers will open in May so if you're interested in speaking at this inaugural event, be sure to keep an eye out for that.
Be sure to subscribe for updates as they're released and keep an eye here for more announcements about the event as they come.