And more than three-quarters of all mining professionals are either looking for a new job or plan to in the next year, with job security and poor management cited as major reasons.

The 2022 salary guide from recruitment firm Hays has found that 42 per cent of mine employers will give a salary boost at their next review - but it will be by less than 3 per cent.

That's less than what what two-thirds of mining professionals think would reflect their performance - they say an increase above 3 per cent would suit.

But the Illawarra's district vice-president for the miners' union the CFMMEU, Bob Timbs, said these figures were averaged across Australia and unlikely to be representative of Illawarra underground coal miners.

"If that's a trend throughout Australia I don't think we're going to see an exit of 70 per cent of our workforce in the Illawarra coal mines," he said.

He said after the pandemic and its travel restrictions local workers were not keen on fly-in, fly-out work.

Mr Timbs said concerns over job security were likely to be caused by changes in workforce structure.

"It's the amount of contract labour they're using," he said.

"What we're seeing in the Illawarra is that the large coal mine owners in the Illawarra have moved to using precarious workforces - there's probably more contract workers than there are permanent employees. And what comes with contract employment is insecure work."

He said pay changes came through new enterprise agreements, some of which were being negotiated now.