Key Points:

Meridian Energy is standing by its claim of being a carbon neutral power generator as National lays a complaint about the company's advertising.

National's Climate Change spokesman Nick Smith has told the Commerce Commission that Meridian has to buy thermally generated power during dry years to supply its customers and that is not carbon neutral.

But Meridian Energy spokesman Alan Seay does not believe the advertisements are misleading. He says the company went through a very robust process to be able to call itself 'carbon neutral' and is happy to work with the Commerce Commission if it decides to investigate.