It's common to see such things in a procedure - as if it actually means anything. Trainers often issue a certificate, but it doesn't attest to anything but the fact the client paid the bill! Unless it's an accredited course, certificates are meaningless.
What's more important is that an internal auditor is competent. It's not too difficult to come up with some criteria which shows how an internal auditor is competent to do an audit.
This is spot on. i have seen many people take auditor training outside the company and come back with 0 idea of how to apply what they have learned. When we transitioned to ISO/IATF 16949, we had a trainer (an accredited 3rd party auditor) come on site and provide training. Examples used were from our day to day operation, so future auditors could relate.
Even after they complete training, i do not consider them competent. They did complete class work and get a certificate, but can they put these skills into practice? In order to be released as an internal auditor, they must complete a minimum of 2 internal audits supervised by the lead auditor. If the audits show the required understanding, they are considered competent. If the audits show they dont meet the competency requirements, more supervised audits and additional training is necessary.
My question is not "can they get a certificate?", but do they meet the competency requirements of the organization?