But their reservations go only a small way to explaining why New Zealand has a donor rate of 8.1 per million people, half that of Australia and far below the world leader, Spain, on 35.1 per million.
Some reckon the situation is also partly the result of a lack of high-profile personal tragedies that would encourage people to become donors.
In Italy, the donor rate more than trebled after the parents of a young American killed on holiday in the country agreed to donate his organs and corneas. Seven Italians benefited from the donations.
Yet this argument is also not totally convincing. Jonah Lomu's quest for a kidney donor attracted huge public attention but no significant increase in the overall number of donors.
New Zealand's low rate probably relates mostly to the lack of clarity over the highly distressing situation that arises when a body suitable for organ donation is kept artificially alive.
On their driver licences, 53 per cent of New Zealanders have said "yes" to being a donor. That might be supposed to be the end of it; if a person has decided his or her organs should be available for transplant, this decision ought to be respected by family members and everyone else.
Yet medical staff tend to require unanimous family consent before they will take an organ. It is easy to see why. No doctor is keen to become embroiled in an argument with grief-stricken relatives. So eager are they to sidestep the issue that the drivers' licence database is not routinely checked.
Some American states have sought to clarify matters by passing laws which dictate that family members cannot overrule a donor's valid declaration.
In New Zealand in 2008, the previous Government sought to tip the balance more towards this outcome by establishing a hierarchy of consent. This provided for individual donors to give "informed consent" to at least two witnesses. They could also nominate a person to pursue donation if family members were reluctant.
But doctors remain in an invidious position under this law. They are required, for example, to consider the family's spiritual and cultural values. In practice, they therefore continue to require unanimous family consent before taking an organ.
The law did, however, point a way towards an increased donor rate by encouraging would-be donors to have an early conversation with their family. This stops families being blindsided by the donor's wishes at a time of considerable grief.
Allied to this must be a more proactive and skilled approach by medical staff to reinforce that wish.
Then New Zealand might start to see more examples of life-giving generosity.