The government is working with mill owners and workers to negotiate support.

Timber mills fear they will be unable to fill orders after the New South Wales government confirmed logging would end in forests gazetted as part of the Great Koala National Park.

The state government announced an immediate temporary moratorium on logging in 176,000 hectares of state forest stretching from Kempsey to Grafton.

The government said the decision would impact six out of 25 mills operating in the region and about 300 jobs.

Details of which mills will close and where jobs will be lost are yet to be announced as the government negotiates assistance deals with owners and workers.

Pentarch Forestry, which stood down 38 workers at its Koolkhan sawmill in March, citing a shortfall in logs from the state's Forestry Corporation, was likely to be among those affected.

Director Steve Dadd said it was too early to speculate on what the future held.

"The government has announced the park and a moratorium on supply but no guidance yet on how critical supply to the housing industry will be served or what support for workers to be retrenched will be offered," Mr Dadd said.

"Our priority will be on trying to comfort very concerned workers, customers and suppliers."

After years of talks, timber mill owners said phasing in a logging moratorium would have helped with planning.

Mill owner Andrew Williams, of the 75-year-old Williams Timbers business in Bucca, north-west of Coffs Harbour, said the immediate moratorium on logging added confusion.

"It's something that I wasn't really prepared for, at such short notice."

Mr Williams said the decision could jeopardise his ability to fulfil contracts to supply power poles to Victoria, railway sleepers and fencing to Queensland and bridge timbers in New South Wales.

"Depending on what is allocated, it will be hard to fill orders," he said.

NSW Timber president Andrew Hurford said the industry was "shocked and disappointed" with the announcement.

"We're certainly having to deal with workers and contractors who are extremely distressed and disappointed and really just trying to come to grips with this unnecessary decision," Mr Hurford said.

He said the move would significantly impact hardwood supply on the NSW north coast.

He called on the state government to meet with the timber industry to discuss how the production of Australian hardwood could continue.

"We hear a lot about the commitment to the Great Koala National Park but [NSW Premier] Chris Minns also made a commitment to a sustainable timber industry," he said.

"Hopefully additional plantations will be a part of that [and] another important part is that we remove obstacles to managing our private native forests so we can continue to build on that supply."

Support for workers

The state government announced a worker and industry support package for those affected, as well as $6 million in community and business support.

For workers, that included Job Seeker-style payments equivalent to their wage and free access to health, legal, and financial services, as well as training support.

Tony Callinan from the Australian Workers' Union said the offer fell short.

"There's local communities on the Mid North Coast that have a strong reliance and a proud history in forestry and harvesting," Mr Callinan said.

Minister for the North Coast and Small Business, Janelle Saffin, said it was a difficult decision to stop logging in the forests.

"You're doing something as a government for good and to ensure that our grandkids get to see koalas in the wild, so they won't be extinct," she said.

She said the timber industry and unions had been involved in consultation about the koala park, and it was always on the cards to include all of the region's state forests in the national park.

"This is not unknown in the sense that it was a clear election promise of the Minns government," she said.

"There's been two years of work around this.

"We've done the full 176,00 hectares [of state forest].

"To do less, we wouldn't have been able to protect koalas from extinction."

Ms Saffin said Essential Energy's transition from timber poles to composite poles had impacted the industry on the Mid North Coast.

She said timber plantations grown for harvesting would remain accessible to loggers.

Ms Saffin said she would continue speaking with mayors and local MPs to support affected workers.

Forestry Corporation NSW declined to comment.