Visiting HongKong in tourist visa.Wants to visit Macao.

Hi, My parents are visiting Hong Kong on the L type. They hold a Nepalese Passport.They would like to visit Macao for couple of days. Even though I am a HKID holder I think my parents need apply one to visit Macao.Please help me to know the procedure. Where to and how long it will take to get approval or the easiest and fastest way. What are the requirements. Thank You