The Commerce Commission has issued a formal warning to the Timaru-based electricity lines company Alpine Energy for too many power failures.
Commission deputy chairperson Sue Begg said Alpine had failed to invest sufficiently in maintaining or replacing overhead lines that it knew were old, or prone to failure in bad weather.
"In this instance, we considered a warning was sufficient as Alpine was taking steps during the period when the breach occurred to improve the condition of its overhead lines and increase tree trimming and removal."
She said Alpine was on notice and any further breaches could result in legal action or a fine.
The Commission regulates lines companies, the charges they make and sets performance standards such as the number of interruptions or outages.
Other lines companies have complained the standards are too strict and don't take into account the increasing instances of bad weather.