Mighty River Power expects it would take at least five years for the Labour and Green party's new electricity policies to be enacted, and John Key says it won't happen.

Investors who applied for Mighty River Power shares have been given a deadline to withdraw their applications if concerned about the Labour-Greens' power policy plans.

Labour's proposed shake-up of the energy sector could slash up to 20 per cent off the value of Mighty River Power although analysts rate the chances of the Opposition's plan going ahead at less than 50 per cent.

The Government said it would file a supplementary disclosure to the Mighty River Power share offer to take into account possible additional risks to investors that electricity reform under a Labour/Greens government could pose.

As Mighty River Power's boss prepares the State-owned company for sale, he has slated the new Labour-Green electricity policy as "socialist".

Matt McCarten looks at the plans of Labour and the Greens to set up an electricity agency, NZ Power, if they are elected next year.

John Key's partial privatisation programme was dealt a major blow this week when the Labour Party announced proposals to regulate the industry, writes Brian Gaynor.

Labour and the Greens are promising a major intervention in the retail power system in a bid to lower residential power prices if they win next year's election.

The Government says it won't be able to say how many people have applied to buy shares in Mighty River Power until after the offer period has closed.

Potential Mighty River Power shareholders have had plenty to digest and dissect since the prospectus for the part-sale of the state-owned enterprise was released this month.

Brokers and analysts are predicting a strong take-up of Mighty River Power shares as the offer opens to the public today.

How a company makes its money and the risks involved are the two main points to focus on when reading through an investment prospectus, say finance experts.

Market players are divided over the attractiveness of Mighty River Power's bonus scheme and say it's hard to know if it will encourage investors to keep hold of their shares.

A startling aspect of the 73 per cent pay rise for directors of Mighty River Power is that John Key says it is "realistic" and "sensible" to do it now, writes Judy McGregor, before the company is listed on the sharemarket next month.

Mighty River Power has warned would-be investors of a long-term drop in electricity prices which would hit the value of its shares should the Tiwai Point aluminium smelter close.

The long-awaited Mighty River Power prospectus is finally available.

The Government has set a price range of $2.35 to $2.80 per share for the partial privatisation of Mighty River Power.

A 73 per cent pay rise for Mighty River Power directors is "realistic" and it is "sensible" to do it now before the company is listed on the sharemarket, John Key says.

Mighty River Power directors are to get a 73 per cent pay rise, it has been confirmed ahead of the release of offer documents for the company's partial float tomorrow.

The partial sale of Mighty River Power (MRP) has created enormous debate and disagreement.

Rio Tinto - the ultimate owner of the Tiwai Pt aluminium smelter - is no stranger to playing hardball with governments when it comes to securing energy contracts.

It is a bit soon for consumers to start relishing the prospect of lower power bills because the future of the Tiwai Pt aluminium smelter is shaky. A deal may yet be done.

The partial sale of Mighty River Power is unlikely to be stopped by even complete failure of negotiations between Meridian and Pacific Aluminium over the Tiwai Pt smelter's electricity price, a broker says.

The Tiwai Pt power price stoush will probably have a small negative effect on the price of Mighty River - but it's not a showstopper say sharemarket analysts.

The Government has opened discussions with Tiwai Point aluminium smelter's ultimate owners Rio Tinto in a bid to broker a deal after talks between the smelter and Meridian Energy reportedly broke down.

Tiwai Pt aluminium smelter's owners have contradicted a report from Meridian, saying they think a power deal can be agreed on.