The Green Party says the Government is desperate to quickly offload three state-owned power companies it is partially selling.
The share offer for Mighty River Power, the first company to be floated, does not close until 5pm on Friday.
But already the Treasury is looking to the initial public offerings (IPOs) to sell up to 49% of Meridian Energy and Genesis Energy and suggests this could happen before the end of this year.
The Wall Street Journal reports that six banks have been invited to pitch for lead roles in the upcoming share floats.
Green Party co-leader Metiria Turei says the Government wants to make a quick buck.
"National and John Key are absolutely desperate to sell off the energy assets as quickly as they can. They want to do it before the referendum (on asset sales) is held because they don't want to hear or be influenced by the public opposition to this policy."
In a statement, The Treasury said ministers have indicated publicly that they would like to see at least one more IPO in 2013, depending on market conditions and how ready the companies are.
No decisions have been made about which company will be next, or the timing of any offer.
Mighty River Power is due to be listed on the New Zealand Stock Exchange on 10 May.