The numbers also show a projected cut of 65 per cent by 2035, behind a target of 70 per cent.
The forecasts are based on current tracking using planned abatement measures.
Campaigners say the figures call into question decisions to approve the expansion of multiple coal mines, which contribute to stationary and fugitive emissions as part of the forecasts.
Legalise Cannabis MP Jeremy Buckingham labelled the figures "an alarm bell everyone in NSW needs to pay attention to".
"My support to this government depends on them being serious in their action on climate change," he told reporters on Wednesday.
"They cannot continue to approve new coal and gas projects and they have to act to address the backwards slide in our greenhouse gas targets."
Independent Wagga Wagga MP Joe McGirr said rural and regional communities were feeling the effects of climate change more strongly than others.
"Regional communities are putting in a lot of the hard yards supporting the infrastructure for renewable energy that's going to save this state.
"We don't want to see those hard yards … blown away on more coal projects."
The state government passed laws in November with cross-parliament support that require a 50 per cent cut in greenhouse gas emission by 2030 and a 70 per cent cut by 2035 on the way to net zero emissions by 2050.
Anti-coal mining campaigners Lock the Gate called for further investment in and support for clean-energy alternatives.
"It's clear the massive pipeline of proposed coal projects must not go ahead if NSW is going to have any chance of getting back on track and meeting the legislated targets," the group said in a statement.
The NSW government has been contacted for comment.
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