The party says its three-part plan, announced in Singleton on Wednesday by Shadow Minister for industrial Relations, Industry and Resources Adam Searle, would improve job security and working conditions if Labor wins Saturday's state election. 

The party's promise involves requiring mine owners and operators to directly employ at least 80 per cent of the workers on that land. That condition would apply to future approval applications including modifications and variations. 

If introduced, the scheme would also require labour hire companies to comply with workplace laws "including providing the same pay and conditions as those enjoyed by directly employed workers". 

Labor also proposes to strengthen a test in the Mining Act that would require companies to engage in safe and fair workplace practices, including dispute settlement procedures, to continue holding or initially obtain any mining approvals. 

The CFMMEU issued a statement on Wednesday arguing the policy would "put mine operators on notice that they can no longer get away with rampant casualisation". 

CFMEU Northern mining and NSW energy district president Peter Jordan said there were mines in his district, which encompasses the Hunter, where up to half the workforce was casual and earning less than permanent staff. 

"It's wrong," he said. "We need political representatives that support the coal mining industry and also support the rights and conditions of coal mine workers."

Mr Jordan said the Coalition had promised a right to request permanency. 

"All they are proposing is the 'right to request' permanency from the boss," Mr Jordan said. " But imagine what happens in the real world when a casual employee actually makes that request. They're likely to get sacked."

Mr Searle challenged the National Party to sign onto the plan.

"We know that many disputes arise because big mining companies want to casualise and contract out their work," Mr Searle said.

"This is bad for workers and the resulting disputes have disrupted the NSW coal supply."

"There has been too much contracting out of jobs in the industry, undermining the economic security of local workers.

"That has to stop, and Labor has a positive plan to work with companies and workers to ensure, decently paid jobs and a resilient industry."

Responding to Mr Searle's challenge, incumbent Upper Hunter Nationals MP Michael Johnsen accused the party of "siding with the Greens to shut down the coal industry by 2030". 

"This is a desperate attempt by Labor to save face when they constantly talk about shutting down the coal industry," Mr Johnsen said. 

"Labor have abandoned coal miners in the Upper Hunter and have done so for many years. 

"[For] what other businesses do Labor want to mandate employee numbers?

"Labor just needs to support the federal coalition's bill in parliament to fix the problem of casualization in the black coal industry and bring it into line with all other awards." 

Upper Hunter Country Labor candidate Melanie Dagg said that she knew "casualisation and insecurity can cause significant stress and financial hardship to workers and their families". 

"Mr Johnsen calls for Labor to vote for phantom federal legislation, which he knows full well his Liberal and National colleagues will never bring on for a vote in the Federal Parliament," she said. 

"It also won't provide the protection coal workers need.

"Only Labor will provide the security and protection for workers in the coal-mining industry."

NSW Minerals Council said commitments in other areas could preserve the industry in the state.  

"The best policy to ensure job security for Hunter coal miners would be a give a strong public commitment to the long-term future of NSW coal exports and not give preferences to the Greens," chief executive Stephen Galilee said. 

In December last year a federal parliamentary committee called for a review into the use of labour hire workers and the number of casual mining sector employees. 

A submission from the Constructrion, Forestry, Maritime, Mining and Energy Union had called for government to address the "insidious" trend that had created an "explosion in the use of labour hire workers by the big mining companies" since 2012.