If the production item does not meet the quality / standards of ISO then do you have to review the Manpower skills, Machinery or Techniques?

ISO complaince is based on eliminating non-conformities from the process and is dependent upon the quality of inputs, training of manpower and infrastructure.  If your Input is of bad quality, output will be defective. Eliminating the waste in process is the key of Quality output which is also linked with the 'Right at the First Time attitude' that reduce cost of quality and rework from the process. Hence yours inputs are very important that can be Man, Machine and Money or combination of these which contribute to the out put and a correct and optimum process is the tool.

You need to review back the PFMEA because in PFMEA you can review all item, Risk Assesment,  method (technic) to work such as poka yoke & jidoka and  action plan that you need to taken to prevent quality issue,

Nice question. (All OF THEM ) First of all in order to achieve a given goal its very important for the basics to be in place, that answers your question.

Thanks for invitation,

I do believe that all of these factors has to be quite reviewed carefully by The Quality Control Management".  

Is there a quality control department in the manufacturing facility or not? 

Reviewing quality control activities can spotlight which area is defective, is it the materials, processes, machines or what. 

The first question to ask is - do you even need to have an ISO Certification in your line of business?

Manpower Skill matters primarily which must get reviewed ..

Technique always gets lead by skill  

And without skill no Machine can produce quality ...

So,,SKILL is the only area needs to get review 

None of these, at least not at first.  Start with the senior management: do they really want to meet the ISO?  Are they willing to do what it takes to make it happen?

Then the junior management.  Are they really trying to meet the ISO?  Are they competent to meet it?

If the senior management want it to happen, and the junior management have bought the right machine and hired the right staff, then the standard will be met.  If there is a failure, then the machinery operators will usually be able to tell the junior management what the problem is: they need a new machine, or better quality parts, or more training, or whatever.

Remember, when something goes wrong in business it is the manager's fault.  Always.  It is the first principle of management.

Techniques obviously or practices followed by the in-charges till now. Then surely you have to look into machinery and technicality of your labor.

In my view, the order to review must be in the sequence of Type of Techniques, Machinery followed by Manpower skills 

It's mandatory to consider the quality of inputs which is always directly proportional to quality of outputs

If does not meet quality, first we have to check the actual product and check the 

A) Raw material Quality and performance

B)  and check the Manpower skill