New analysis suggests the Government's changes to the Emissions Trading Scheme (ETS) could put forest plantings back by up to a decade.
The amendments being introduced to Parliament on Thursday are designed to soften the scheme's impact.
Euan Mason, from Canterbury University's School of Forestry, says planting pine trees for carbon storage will become viable when credits from the trees already growing are sold out.
He says his calculations show that that was due to happen in 2013, but the Government's changes may push it out to at least 2020.
In Mr Mason's view it is unlikely that the Government's wish for new plantings of 50,000ha a year until 2020 will now be met.
The spokesperson for the Kyoto Forestry Association, Roger Dickie, says foresters are worried there won't be a market in New Zealand for their credits and they will have to sell overseas.
But forestry consultant Owen Springford says he already has investors lining up to meet a huge expected demand for credits from the energy and transport fuels sectors.
Why do it with marginal support? - Goff
Labour leader Phil Goff says he cannot understand why the Government is willing to pass major legislation with marginal support.
Talks between Labour and the National Party over changes to the ETS broke down after National annouced a deal with the Maori Party.
The Maori Party agreed to support the Bill to the select committee stage, but negotiations about ongoing support are continuing.
Mr Goff says National appears to be happy with a marginal level of support for a scheme that should last for many years.
But Prime Minister John Key says he's confident of Maori Party support right through the parliamentary process.
The select committee will test ideas and concepts, he says, but in broad principle the National Party has the backing of the Maori Party.