Institute chief executive Ralph Chivers said it was difficult to make direct comparisons but stock market listing involved greater risks. "By and large Government sector as a collective tends to be lower than private sector for broadly similar roles. You could easily run an argument that an SOE is less risky than a listed company."
Chivers said boards of state-owned companies might need a different range of skills if they were listed.
"For a company that's going through a process of listing for the first time or doing a lot of acquisitions you require particular skills and particular types of decisions. It might be that you look at fees paid for that."
Remuneration was not straightforward. "For a listed company there is a higher degree of risk or perceived risk in taking on that role than in a government environment."
The energy companies tagged for partial sale, in addition to a greater stake of Air NZ, are headed by vastly experienced chairs Joan Withers, Chris Moller, Dame Jenny Shipley and John Palmer. But like all SOE board members they are appointed by the Government.
Shareholders Association corporate liaison Des Hunt said because of this political process some boards had been weakened. Different skills would be needed, he said.
While his analysis showed directors were due a pay increase, it should be very closely linked to returns.
"There should be an increase in directors' fees but rather than put them up straight away they should be phased in over three years based on performance and if necessary make changes."
Chivers said there were "probably" enough good quality directors to sit on partially listed companies. "It would be no surprise that the pool of people who would be good quality candidates is not large."