I was fortunate to be in Singapore in 2017 for a conference (those were the days!) and attended the signing of the INSHPO document.
I recall feeling dismayed to read the pages of description as INSHPO used hundreds of words to try to distinguish between 'practitioner' and 'professional'.
As Peter Blake might have said, does all this effort to define two supposed categories make the boat go faster? Does it prevent more worker illness and injury?
Happy to be enlightened.

All the following is my humble observations and opinions.
Starting from end before moving to the start, I don't know what Peter Blake may have said. What I'm aware of after observing several Americas Cups on TV is there are many roles that people have on the boat/yacht. I have yet to observe the helmsperson doing grinding. I can only conclude that if people have roles and do their tasks within the context of the objective (providing the objective is clearly outlined) then the boat should go faster. Of course there are some presumptions there since a vast array of factors have not been mentioned.

Getting back to H&S, would defining the roles of people in the H&S profession "prevent more worker illness and injury?". Possibly yes, maybe no. My thoughts are defining roles would have an effect beginning at management level.

I think H&S governance in NZ is still in it's infancy. The focus appears to be on production with reduced labour. H&S at governance level appears to rely on statistics that bear little relevance to manage risk. The reliance on overseas methodologies and preponderance of safety documentation are an attempt, I believe, to primarily safeguard management from legal liability. WHS lawyer Greg Smith talks about the delusion of health and safety reporting here - https://safetyrisk.net/everything-is-green-the-delusion-of-health-and-safety-reporting/ . The comments from the Pike River Royal Commission still ring true today.

I agree Peter, there is a lot of surplus words in the framework. Once I'd read it I took out what I needed, namely pages 11 and 16-21. I already knew about 46-47.

If H&S roles were defined as on pages 16 to 21 of the INSHPO, management should have a clearer picture of what the person being employed can do. HR departments could identify the position requirements. Applicants would know what they are applying for.

Defining the roles between Practitioner and Professional opens a pathway for H&S representatives to follow. Not only is there a difference between tactics at worker level and strategy at management heights, but also the training beginning with vocational. Academic studies need to be worked towards once people get out of the mode of learning.

According to MBIE there are 530,000 small businesses that make up 97% of all enterprises. For this, a small business is 1-50 people. The full data is here - https://www.mbie.govt.nz/business-and-employment/business/support-for-business/small-business/ . These guys require value for money since they generate 25% of NZ's GDP. By defining roles and profiles as described in the INSPO Framework a number of issues may addressed.

These include opening a new market for the H&S profession, standardising H&S objectives, revising positions from fulltime to contract, businesses getting what they need and improving cultural maturity.

For the remaining 3% of enterprises that are large, generate the remaining three quarters of the GDP and employ the other 72% of the workforce, the requirements that management and workers need become clearer so the issues above are addressed. Then possibly H&S could be worked towards risk management (https://safetyrisk.net/proving-safety/) and starting when safe (https://www.youtube.com/watch?v=j2ROcAdoGDU)

How would it work? Could it work? That would depend on if the H&S profession was looking at the doors that will close rather than watch for the opportunities that will open up.

Gee that's a lot of rambling . . .

I'm reading with some bemusement that we still refer to NZ's health and safety governance as being in its infancy. The first Act came into being in 1992 - we are now in 2021. We, as professionals/practitioners need to stop enabling businesses to continually play that card. Before the first Act we have the Factories Act which also set out standards and requirements.
We need to be more proactive in this space and stop waiting for government to tell us what we need.
We need to be setting standards for good health and safety practices and people who deliver the information and services to businesses.
I prefer the term professional to practitioner as the latter is a term used in the health field but I don't see it as a show stopper or even worth worrying about.
We need to take charge and set standards that are aligned with ISO 45001 with all businesses and work hard with the owners and leaders to help them understand that good health and safety practice is good business sense.