Can I apply for 1 or 2 weeks extension on top of the 14 days allowable for entering HK?

Hi, it is ok for you to extend your stay from HK Immigration department directly if 14 day duration is not enough. But you have to show documents covering your stay there, such as hotel reservation, return ticket or invitation letter from a local sponsor.
BTW, you are advised to contact the immigration department directly because I heard from someone else that 14 day visa exemption for Philippine passports had been suspended days ago.