TrustPower hopes to raise $125 million through a senior bonds issue.
The electricity generator and retailer will be offering 75 million five-year senior bonds, attracting 7.6% interest, and 50 million seven-year senior bonds at 8% interest.
TrustPower says it will use the money for general corporate purposes, including the repayment of debt.
The offer is expected to remain open until 18 December, and there is provision for up to 50 million in over-subscriptions.
ANZ and Craigs Investment Partners Limited have been appointed as joint lead managers and Bank of New Zealand has been appointed as co-manager.