The concept of good faith pretty much underpins employment agreements world wide; whether it is provided for in the country's respective employment legislation (such as New Zealand and Australia), or is implied by the act of entering into an employment contract.
Employers can often struggle with the concept of good faith, as many times the requirement to act in good faith generally occurs where the employer needs to make a "business decision" (such as restructuring, redundancy, poor performance etc), and the employees are a secondary component in the equation.  Generally in instances such as this, the businesses may seek legal advice, either through their in house HR team or at times independently.
Lawyers have a very specific purpose in this process, and that is to provide legal interpretation around the tolerance for the employer to act within that is provided for in the respective legislation, and to provide legal council and representation should it all go pear shaped.
What lawyers generally are unable to do is to provide the moral and ethical aspects around what good faith means, and this is where your HR partner should be able to step up and assist.  A good HR partner should not only be able to advise the employer of the legal implications of what the business is attempting, but should be able to bundle this up within the aspects of what good faith should provide for. 

Seeking HR advice at the start means that a business can not only have a higher level of flexibility in the execution of business decisions, with less costs associated for procedurally deficient processes; but can still deal with its employees in a legal, ethical and moral capacity.

So as a starting point, and an introduction to me, I just need to let you all know that I do not believe in "Tea and Tissue" HR.  You know the role, where the HR person is predominately the facilitator between employee and employer.  This sort of situation means that HR never actually enable the manager to undertake the people management role of their job, and it is my opinion that this unintentionally creates a division between employee and employer.

Do you know what I mean?  Maybe the following conversation might help:
Employee - "HR lady, my manager has declined my leave application, and I need to go and see my sick grandmother, please help"
HR person - "That is terrible, sit down and tell me all about your grandmother, you must be in pain..."
HR person to Manager - "Why did you decline employee's leave request, their grandmother is very sick, and it seems a little mean to not let them go see her ... it is not what a good employer would do!"
Manager - "Oh, I didn't know, the employee did not tell me why they wanted leave, of course they can go see their grandmother - I am not a bad manager after all, and I do care about my staff"
HR Person to employee - "All sorted, I spoke to the manager, and they have approved your leave - I hope your grandmother gets better" (cue superhero music...).

OK, I admit it is a little tongue and cheek, but you get the gist.

I have to be honest, I was this sort of HR person, back in the olden days - and I have to admit, it is a pretty powerful feeling :-)  You come home exhausted day after day, but pat yourself on the back for all the conflict you resolved.  Slowly but surely you start to look at the managers you are assisting as muppets, and wonder just how it is they every got their jobs, and you cant quite seem to understand why the boss doesn't recognize just how critical you are to the organisation.

This sort of HR can add value, and I know some employers really value this type of HR, but it aint for me... I actually think HR can add strategic value to an organisation, you know, increase profits, create better leaders, change the world!!!

Seriously, I know that there is a lot of debate out there, around how HR can provide its services (ie centralised, decentralised, Shared services etc) - but the question I pose to you, is do you think it matters what the philosophical values of HR are within in an organisation?