The issue was, we already had a system that could achieve the same options, she said.
The Crown responded to the report by saying there simply wasn't time to rehash the ETS.
Shaw said the Government was committed to retaining the use of forestry offsets for carbon dioxide and other greenhouse gas emissions.
Shaw and Forestry Minister Shane Jones later announced a change to the ETS that will change how forest owners are paid for the carbon their trees absorb from 2021. The changes were brought about by prompts from the forestry sector wanting a simpler accounting method that would incentivise planting trees. Jones told RNZ: "By taking a long-term view of the amount of carbon in a production forest, forest owners will be able to trade more carbon at lower risk, and not have to worry about finding units to repay when they harvest."
Meanwhile, Greenpeace said Upton's report seemed to have been influenced by the agricultural lobby.
Greenpeace adviser Steve Abel said while the report had some merit, it continued to treat dairy with kid gloves because it focused on offsetting the highly potent greenhouse gasses nitrous oxide and methane rather than actually cutting them.
"We expect the champagne corks will be popping at Ravensdown and DairyNZ this afternoon, because they are being let off the hook once again," he said.