Israel's main labor union threatened on Monday to shut Israel Chemicals (ICL) main Dead Sea potash operations if the fertilizer and specialty chemicals maker does not revise a plan to cut jobs.

ICL workers have been on strike for two weeks at the company's less critical bromine division over a plan to cut the 900 workforce at its bromine plants by 140.

"On Wednesday, if the issue is not resolved, sadly, a strike will begin at the Dead Sea Works," Avi Nissenkorn, head of the Histadrut labour federation, said at a protest with ICL employees.

ICL, which has exclusive permits to extract minerals from the Dead Sea, is one of the three largest suppliers of the crop nutrient potash to China, India and Europe. Extended disruptions would almost certainly hurt its market share in the near term.

The company called on the workers union to return to negotiations over its proposed efficiency programme and avoid an "unnecessary strike".

ICL's chief executive said last week he hoped 2015 would show a turnaround after a year of restructuring and cost reductions hurt the company's bottom line.

In its quarterly report, the company said labour interruptions at its Dead Sea operations lowered fourth-quarter sales by $60 million.

ICL is controlled by conglomerate Israel Corp.