Shaw said New Zealand was "showing leadership" by committing to the review to ensure the target was ambitious enough.
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The Paris Agreement required action from all countries, and targets were expected to strengthen over time.
"The Paris Agreement was a turning point," Shaw said.
"It was the moment that virtually every country in the world decided that, if we are to hand our children a safer future, we need to act.
"As a government fully committed to solving climate change, it's only right that we get expert, trusted and independent advice on whether our international targets are consistent with that goal."
Government emissions projections last year showed the country falling woefully short of its Paris commitment, with just a 9 per cent reduction in gross emissions expected by 2030 on 2005 levels.
The latest greenhouse gas inventory, released this month, showed New Zealand's emissions had barely budged in recent years, and the country continuing to rely on plantation forestry to soak them up to meet international obligations.
"There is a long way to go, but we are starting to bend the curve towards a climate-friendly future in New Zealand," Shaw said.
He pointed to the Zero Carbon Act passed last year, which enshrined the 1.5C goal in domestic legislation, and Climate Change Commission as examples of actions taken.
"If they conclude there is more we need to do, the Commission will provide recommendations on how best to align our international targets with the Paris temperature goal. This will ensure we are playing our part globally," Shaw said.
However, critics say while more has happened than in previous governments in terms of setting policy, there was still little action.
"It would be much more effective if the Government actually enacted some policies - like a carbon tax in the transport sector, some vehicle emissions standards, and so on - that might move us along in terms of beginning even a tiny bit to walk towards the commitments they have already made," said Professor Dave Frame, director of Victoria University's New Zealand Climate Change Research Institute.
He also questioned setting targets against a global target, which was reliant mostly on the performance of other countries.
Instead, he suggested New Zealand set a target to limit its own warming by a given date - as the United Kingdom had done, fix a date by which New Zealand was at net zero CO2 and had lower than current levels of methane, or choose a warming level for New Zealand and aiming not to exceed it.
"All those are things countries can do, where success or failure is up to them. Our 1.5C-compatible logic is not."
In its review the Commission was expected to consult with a wide range of people, including iwi and hapū, industry, technical experts, special interest groups and sector leaders.
Shaw urged other countries to also review their commitments, and said he had informed an overnight meeting of the Alliance of Small Island States.
The review was also to factor in changes in science since the commitment was lodged in 2016, particularly the IPCC's 2018 Special Report on Global Warming that painted a grim picture and urged more action.
Along with the emissions target review, Shaw also requested advice from the Commission regarding New Zealand's biogenic methane emissions, the most controversial aspect of the zero carbon law.
The current target is for a 24-47 per cent reduction by 2050 and 10 per cent by 2030, but Shaw has requested the commission review how this relates to the 1.5C target and understand potential reductions that could be required.
The Commission is expected to provide its recommendations early next year alongside its advice on emissions budgets.
Countries were expected to unveil their renewed pledges at the next global climate change meeting in Scotland this year, however due to Covid-19 it had been delayed.
The review comes as the Climate Change Commission, along with a group of environmentally-focused NGOs, have been calling for the Government's to apply a "climate change lens" to its Covid-19 economic recovery and not lock New Zealand into a high-emissions future.
East Coast iwi are also calling for the Government to back a "shovel-ready", job-creating and climate-conscious project to save the Raukūmara forest that is dying under a plague of introduced pests.