The Government is negotiating with iwi leaders to win Maori Party support for legislation amending the Emissions Trading Scheme.
The deal would allow Maori foresters to plant trees on conservation land that is deemed marginal, and to claim the carbon credits.
Talks on the amended bill between National and the Maori Party are intensifying after the select committee was unable to reach agreement on Monday.
The Climate Change Response (Moderated Emissions Trading) Amendment Bill will now return to Parliament unamended.
The Maori Party tabled a minority report raising concerns about the bill.
But the Minister for Climate Change Issues, Nick Smith, says he's confident he can win the party's support to get the scheme passed into law by Christmas.
He says afforestation is just one of a number of issues the Government is discussing with iwi leaders and the Maori Party as part of continuing negotiations.
The Government says the bill should proceed as drafted, but Labour, the Greens and ACT disagree.
Changes could add $110bn to national debt
The proposed changes are expected to increase debt by $110 billion by 2050.
They would involve free allocations of carbon credits to industries facing international competition.
In its minority report, the Labour Party says Treasury officials told the committee that the bill could increase Government debt by up to 17% of GDP by 2050.
The party's leader, Phil Goff, says that is unacceptable.
"This represents a blow out of $110 billion on the costs of emissions trading. For the average New Zealand family this means a burden of $92,000 to pay for national's scheme."
The Green Party co-leader, Russel Norman, says mistakes made by officials working on changes to the emissions trading scheme highlight the rushed nature of the process.
Mr Norman says Treasury officials admitted to committee members in a closed session they had made some errors in their calculations.
"Originally they said the cumulative increase in Government debt was going to be 6-8% of GDP by 2050. In fact the true figure is 13-17% of GDP by 2050.
"That is, Treasury made a $50 billion mistake and it is taxpayers that are going to have to pay that amount."
Accurate predictions impossible - Smith
However, Climate Change Minister Nick Smith says the numbers are not credible.
He says figures beyond the first decade of the scheme are highly speculative.
" The question beyond 2018 is what carbon price to assume, what international agreements to assume and what assumptions are to be made about the degree that industry might grow.
"Now, if you take an extreme view of those - and scenarios that have been done by Treasury include different prices of carbon - you can come up with those sorts of numbers."
Dr Smith also says amendments to the emissions trading legislation need to be hurried through because the existing "flawed scheme" is due to take effect on 1 January.
The bill will return to the House and face three further debates in Parliament, including the committee stage when any changes will be made.
Mr Goff said Labour would repeal the bill.
Govt on track for Copenhagen - Smith
Dr Smith believes the Government remains on track to pass the legislation before the United Nations climate change conference in Copenhagen in December.
The Labour Party is urging the Government to slow the process down, due to the potential for costly mistakes.
About 190 nations will gather in the Danish capital from 7-18 December to work out a global deal to fight climate change after the first phase of the Kyoto Protocol ends in 2012.
Talks so far have been clouded by disputes between rich and developing nations.
Dr Smith says New Zealand will not follow Australia's lead and exclude agriculture from the Emissions Trading Scheme, saying the Government remains committed to an "all gases, all sectors" approach.