Applicants for visas must be of good character. You may have to supply a police certificate (or similar) as evidence of good character, depending on which policy you apply under.
Police clearance certificates must be less than six months old when the application is lodged.
We may ask for further police certificates if the initial police clearance certificate becomes a year old from its date of issue before we make a decision on your application; or within the 12-month period if there is good reason to do so.