Taite said he believed there needed to be more financial education first.
"I just don't think the New Zealand public is ready to be buying shares. The assumption is that people understand what they are buying."
Taite said he expected institutional investors including KiwiSaver schemes to buy a lot of shares and that was probably where members of the public should be getting access.
Others were frustrated that the bonus share offer will not be accessible to all investors.
Rickey Ward, head of equities at Tyndall Investment Management, said it was disappointing the bonus offer would not be open to institutional investors including KiwiSaver schemes.
"We are managing the money on behalf of New Zealanders - why shouldn't we be entitled to it as well?"
Ward said the bonus share scheme would potentially be difficult to administer because of large numbers of small investors. He believed it would have been clearer to cap foreign ownership in the floats.
"It's more complicated, which means there could be more problems. And that's just what you don't want to see for an SOE float."
But New Zealand Shareholders Association chairman John Hawkins said the $1000 minimum investment level would make the offers affordable for a large number of people and the bonus would encourage investors to take a longer-term view.
Hawkins said extending the bonus offer to institutional investors including KiwiSaver schemes would be impractical because the Government would have to sell down significantly fewer shares to start with.
Mighty River Power is due to be the first of four energy companies to be partly privatised - up to 49 per cent - the others being Genesis, Meridian, and Solid Energy. The Government also wants to sell down its stake in Air New Zealand.
Details about the size of the loyalty bonus are yet to be released.
SWEET DEAL?
* Minimum parcel to be worth $1000.
* Must be New Zealand resident or permanent resident to qualify for bonus.
* Ordinary New Zealanders guaranteed up to $2000 without being scaled back.
* Loyalty bonus for individuals who keep shares for three years.
* No guarantee or loyalty bonus for institutional investors.