A group of forest owners and managers have appealed to the Prime Minister in an attempt to persuade the Government to restrict the use of cheap international carbon units in New Zealand's emissions trading scheme.
In a letter to Mr Key, they urge the Government to impose a limit on imported credits, to align New Zealand with its trading partners.
The Government is not proposing any such restrictions in amendments to the ETS legislation.
But one of the forest owners, Roger Dickie, says allowing emitters to buy very low priced credits to offset their emissions will turn New Zealand's scheme into a sham and drive away any new investment in forestry.
He says the Government is allowing units in from Eastern European countries and Russia where there are hundreds and millions of units which are not properly validated.
"The Emissions Trading Schemes in the rest of the world, in Europe, China, Korea, United States, Australia - they don't allow these units, or if they do they allow them in a very small amount and that's why we're saying there should only be 50% of them allowed into our Emissions Trading Scheme.''
Mr Dickie said New Zealand needs 20,000 hectares of new forest a year to meet its emissions targets, but last year, there was a net loss of more than 18,000 hectares.