Djoker,
Kailangang kumuha ng police clearance sa lahat ng bansa na nakapag-stay ka (hindi tourist ha) for the past 10 years. Example, in your case, you need to have an NBI clearance AND Singapore police clearance AND police clearance ng mga bansa kung saan ka nakapag-work.
Since misis mo ang principal applicant, kung sa pinas lang tlga sya nag-work, then, NBI lang kelangan nyang i-submit.
Sa case ko, nag-work ako dito sa Saudi, pagdating ng Medical Request letter ng Canadian Embassy Visa Office sa Manila, I was also asked to submit a Saudi police clearance (translated to english) along with my NBI police clearance.
Hope this helps.
;D ;D ;D