To anyone here I need some opinion in PhD regarding Law area. Anyone know which institution in Malaysia provides such course? Is master degree a pre requisite to do PhD? I have seen some people who did Phd straight after degree

Public universities such as UM and UKM do provide that. Check out their websites, everything you need is there.
Yup, you can choose the fast track without having a Masters degree, provided you graduate your bachelors degree first class. (3.7 and above) and additional requirements as needed by some universities (might be in the form of recommendations, interviews etc).