Australia’s energy and emissions reduction minister, Angus Taylor, has signalled some of the trade-offs the Nationals sought from the Liberals in return for formally supporting a net zero by 2050 target have not yet been approved by the cabinet.

Asked by the ABC on Tuesday night why the government had declined to reveal details of specific promises made to the Nationals, Taylor said various measures would be made public after cabinet had given them the green light.

“As policies get developed and finalised and go through cabinet, they get announced,” Taylor said. “They’ve got to go through the normal process – that’s our Westminster system”.

Taylor’s comments raise the spectre that the Nationals signed on to net zero before elements of their wishlist were fully approved.

The Morrison government, thus far, has been transparent about two of its internal agreements with the National party. The first is that the resources minister, Keith Pitt, has returned to cabinet after being dumped to the outer minister by Barnaby Joyce when he returned as deputy prime minister earlier this year.

The prime minister has also confirmed that the Productivity Commission will conduct regular reviews of the impact of the transition to net zero emissions on the regions.

The Nationals had initially sought agreement from the Liberals that Australia would pull out of the net zero commitment if regional Australia was left worse off. But the Liberals instead agreed to regular reviews of the transition rather than the full safety valve proposal championed by Nationals frontbencher Bridget McKenzie and others.

Scott Morrison and Taylor confirmed Australia’s formal commitment to net zero on Tuesday. The Nationals signed on – even though Joyce told colleagues in his party room that he didn’t support net zero – because a majority of MPs were in favour.

As well as the target, the government on Tuesday released an updated plan outlining their approach to achieving the transition. But that plan has been roundly criticised for its lack of detail and ambition and denounced as a “political scam”.

This is despite the headline figure being broadly welcomed as a positive step in Australia’s long-running climate policy debate.

As Morrison prepares to present Australia’s position to the United Nations climate summit in Glasgow next week, Labor and the Greens attacked the Coalition’s plan for its lack of detail, and criticised the government for failing to upgrade its 2030 target, which will remain set at a cut of 26-28% of 2005 levels.

The government released an updated projection to its Paris target that shows Australia is on track to achieve a 30-35% cut, but abandoned efforts to formally revise the figure based on internal resistance from the National party.

The Greenpeace Australia Pacific chief executive, David Ritter, said the Australian government’s commitment “will not stand up on the global stage”, comparing the commitment with the UK’s pledge to reduce emissions by 68% by 2030 and 78% by 2035, and the US’s 50-52% 2030 reduction target.

He said without an updated 2030 target that did more than just “repackage” state emission reduction targets, the government’s plan was “meaningless”.

“This is a political scam, not a serious plan. Let’s be clear: there is still no credible plan. What we saw today from Morrison was effectively just another fig leaf for inaction,” Ritter said.

The Clean Energy Council said without a stronger 2030 target, there would be no positive investment signal to accelerate the decarbonisation of Australia and “take advantage of the enormous economic opportunity in play.”

“While the federal government has recognised the importance of a commitment to net zero by 2050 emissions target, a refusal to take on greater ambition over the next decade will likely leave Australia isolated and unable to make the most of the economic benefits that come with rapid decarbonisation,” the CEC said in a statement.

Calls for a stronger medium target were also echoed by the Australian Academy of Technology and Engineering, which welcomed the technology-led approach, and said a 50% cut in emissions by 2030 was realistically achievable based on the technology already available.

“Today’s announcement delivers much needed direction as Australia charts its course toward a net zero emissions future. However, we urge the government to develop an implementation framework which guides the way for this technology-led plan with public accountability at the centre,” the chief executive of ATSE, Kylie Walker, said.

“While industry is making great strides, we need strong government leadership and incentives to realise the intentions outlined today,” said Walker.

The National Farmers’ Federation, which had warned that farmers would be punished without a net zero target, welcomed the pledge along with the “tremendous opportunity” to use agricultural land as a carbon sink.

NFF chief executive, Fiona Simson, called for the government to release the “critical details” of the agreement struck between the Nationals and the Liberal party to show how the agricultural sector would be protected.

Morrison refused to release the details of the deal with the Nationals on Tuesday, saying the government would release all of its policies in the lead-up to the election, including details of what it had promised the junior coalition party.

John Connor, the chief executive of the Carbon Market Institute, which represents businesses that buy and sell carbon credits, questioned why taxpayers rather than business were underwriting the transition to net zero. The government has committed $20bn to the technology roadmap, with the expectation this will leverage up to $100bn in additional investment.

“While the 2050 net zero emissions target is welcome, it appears the plan is a missed opportunity to use existing policies as a springboard to a technology and market investment approach that would have business not the taxpayer as the main driver of the plan”, Connor said.

The roadmap released on Tuesday suggests about 20% of Australia’s emissions reduction task will be achieved through international and domestic offsets, but there is little detail about how process this would work.

The institute has been calling for a strengthening of the existing safeguard mechanism that sets carbon pollution limits for large emitters, but which the energy and emissions reduction minister, Angus Taylor, has described as a “carbon tax”.

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The Australian Industry group welcomed the government’s net zero pledge as providing clarity on Australia’s 2050 position, but said a policy framework was still needed.

“The federal government’s decision to adopt a formal economy-wide target of net zero emissions by 2050 will deliver an immediate boost to Australia’s transition, but a lot more work will be needed to flesh out the plan to get there,” chief executive Innes Willox said.

He also said a more “ambitious” 2030 target was still needed, as well as an updated follow-on target to be developed in the next couple of years.

The Australian Food and Grocery Council said it welcomed the net zero pledge and would work with the government to achieve the target, “and meaningful progress on emissions in the interim.”