Rio Tinto's attempt to renegotiate New Zealand's largest electricity contract, for its aluminium smelter at Bluff, comes as the company's chief executive warns of "difficult decisions" ahead.

The Herald on Sunday today launches a campaign for minimum insulation standards for all homes.

Home insulators are hiking prices, claims investors' body.

The many critics of National's troubled privatisation programme may be more than a little premature in celebrating a possible delay in the first share float.