The Member for Shortland and a federal Labor climate change spokesperson said it was important the NSW Government ensures safeguards in its regulatory systems to accommodate sudden global shifts that are a risk to mines in the future.

Mr Conroy was responding to questions about the large number of Hunter mine expansions approved in 2019 and the extent of expansion applications currently being assessed.

They include Glencore's plan to more than double annual production at its Glendell mine at Singleton and operate until 2044.

Its Mangoola mine at Wybong, formerly known as the Anvil Hill mine, is also looking to expand and mine an additional 52 million tonnes of coal. Glencore has also applied to expand its Bulga operations.

Mr Conroy said he was "not going to speculate on their motivations" for expansion and he "hadn't had a conversation with them about their view on climate policy", although he had spoken with the mining industry.

Asked if he thought there would still be coal mined at Glendell in 2044, Mr Conroy said: "I honestly don't know."

In late 2019 Mr Conroy said that "structurally we are close to reaching a tipping point globally where there will be a decline in coal", after a 27 per cent rise in Australia's thermal coal exports since the seaborne thermal coal market peaked globally in 2012-13.

In response to questions about Hunter students objecting to new coal mine expansions, Mr Conroy said he respected and supported their right to object.

"But if we want to see action on climate change we should be concentrating on strong domestic emissions targets," he said.

Mr Conroy criticised the Coalition Government's record on emissions reduction, and said the latest official government emissions data confirmed Australia will not meet even a limited Kyoto Agreement commitment to cut emissions to 5 per cent below 2000 levels by 2020.