About 440,000 New Zealanders have pre-registered their interest in buying Mighty River Power shares in what is shaping up to be the biggest share float in Australasia since the 2010 debut of Queensland's QR National in 2010.

The level of interest, on a per capital basis, was on a par with the second tranche of Telstra offered by the Australian Government in 1999, which attracted about 1.8 million in pre-registrations, equating to about 10 per cent of the Australian population at the time.

Minister of State-Owned Enterprises Tony Ryall said that the number of New Zealanders who pre-registered was "extremely pleasing''.

Pre-registration is not a commitment to buy shares, and someone pre-registering their interest may decide to not apply for shares in Mighty River.


"However, it was a goal of the Government to achieve widespread awareness of the opportunity, and I believe we have achieved this,'' he said.

New Zealanders who have not pre-registered can still take part in the offer when it opens, Ryall said in a statement.

The local initial public offer (IPO) market has been relatively active compared with Australia's and rest of the world's in recent years.