Solid Energy's internet system was hacked overnight.
The hackers apparently redirected the Solid Energy website address to another site that featured a DVD of lignite mining, said the company's general manager, communications, Vicki Blyth.
"It attempts to replicate the front page of our website - quite badly I might add."
Solid Energy realised what had happened only when it received calls from journalists this morning. They had received an email pointing them to the Aotearoa Independent Media Centre website which said the Solid Energy website had been hacked.
No-one had claimed responsibility for the hacking and Solid Energy had no idea who had done it, Ms Blyth said. Solid Energy had referred it to the police.
The company did not believe its website had been compromised, but was double-checking. "It's only an information site, it's not like we're a bank with customer details or any of that stuff."