Strike action by mining supervisors at Appin and Dendrobium mines has been branded irresponsible by Illawarra Coal president Troy McDonald.
The supervisors will stop work tomorrow and next Monday after voting last month to support a range of protected actions in their long-running pay dispute.
The strike action is in addition to ongoing bans on working non-rostered overtime.
The strike will be the second at BHP Billiton-owned mines in the Illawarra in only a few months.
In November, about 50 supervisors at BHP subsidiary Illawarra Coal's Appin mine went on strike for two weeks.
In both cases, the Association of Professional Engineers, Scientists and Managers, Australia (APESMA) has argued that the Illawarra supervisors' base rate of pay was lower than at other NSW mines.
Mr McDonald said the timing of the strike was quite poor.
"At a time when the coal industry and other sectors are under considerable pressure, industrial action by mining supervisors who represent only 6 per cent of the Illawarra Coal workforce will only cause uncertainty to the Appin and Dendrobium mines, other employees and the broader Illawarra community," Mr McDonald said.
He said Illawarra Coal mining supervisors were well rewarded, being in "the top 25 per cent of equivalent roles across the coal industry".
"Mining supervisors received a competitive salary adjustment just four months ago and the company has proposed additional increases to various allowances in its offer," he said. "Our very low level of turnover for mining supervisors across our operations, and the strong demand for these positions with the company, is evidence that we have the balance right."
APESMA's Margaret Buchanan said the supervisors' decision to strike was not taken lightly.
"After five months of negotiations, mining supervisors have no other way to get BHP to take their concerns seriously," Ms Buchanan said.
She said the main stumbling blocks in the long-running dispute were the mine supervisors' claim for BHP to bring their base pay rate up to be in line with comparable NSW mines and to have guaranteed annual increases rather than discretionary increases.
"Dendrobium mining supervisors are currently on one of the lowest base pay rates in NSW and their request to have their base pay rate brought up to NSW standards has fallen on deaf ears," Ms Buchanan said.