Sawmillers say the West Australian government has broken its promise to support timber communities ahead of the ban on native logging.

The sawmillers say they have stopped receiving timber despite the ban not coming into effect until the end of the year.

Forest Industries Federation (FIA) said the state government had guaranteed the timber supply to sawmills from the state-run Forest Products Commission until the industry's closure at the end of 2023.

FIA chief executive Adele Farina, a former WA Labor MP who lost her spot in parliament as a result of a factional deal, said the government had backtracked.

Five months from the cut-off, she said the commission had contacted mills across southern WA and advised them that no more log supply was available.

The state announced an $80 million fund and agreement to help forestry companies and workers to transition into new industries.

Ms Farina said part of the reason the industry had agreed to that deal was the promise of a continued supply of logs.

"Nothing in the agreement removed contractual obligations for sawlog deliveries," she said.

"In fact, it was emphasised that current contractual obligations would be honoured.

Forestry Minister Jackie Jarvis declined an interview with the ABC but provided a statement. 

"Sawmills have contracts with the FPC until 31 December 2023, when the current Forest Management Plan ends," the statement said.

"However, as part of the transition payment deed, log delivery volume obligations were removed under the deed."

While some of the bigger mills have already stopped production, other smaller mill operators have been wondering how they will survive without wood to put through their mills and pay their workers until a new Forest Management Plan is announced in the new year.

Jay Branson owns the Dwellingup Sawmill. He signed a deed of contract with the government last year to receive a compensation package to help him transition to harvesting and milling logs from mine sites and private landowners.

"I did have a contract for approximately 5,000 tonnes a year," Mr Branson said.

"And as the announcement said, at the time, that contract would be fulfilled to the end of December.

"Three weeks ago, we've been told verbally that we're not going to get any more saw logs for December."

While he has stockpiled timber from sources other than native forests, Mr Branson said he was shocked by the FPC manager's phone call.

"We budget upon there being some form of disruptions because of the downturn in the industry, but I did not budget upon it being five months earlier than the end of the contract," he said.

Focus on firewood, not timber

The FIA also claims trees for logging are now selected on suitability for firewood by harvesters, not sawlogs, with concerns about supplies next winter.

"It makes me worry," Mr Branson said.

"I haven't been told that it is going to firewood.

"I've been told that has been walked past, so they're not going to cut, they're not cutting sawmill logs any longer."

Sawmill and forestry consultant John Clark said he had seen clear evidence that sawmill-quality timber was still being harvested, but it was not going to mills and was instead being stockpiled for firewood.

"One of my suspicions is that the minister, the Honourable Jackie Jarvis, is very concerned that there'll be a firewood shortage next year," he said.