COLOMBO, February 5: More than half a million plantation workers in Sri Lanka launched an indefinite strike today, demanding higher wages, which the planters said would ruin their companies.The strike, led by the Ceylon Workers' Congress (CWC) of Livestock Development and Estate Infrastructure Minister S Thondaman, had brought the work in the tea and rubber plantations to a standstill, trade union leaders said. ``The strike is in full swing,'' Thondaman said, adding, it would go on until the planters accepted their demand.He said the workers had earlier accepted Labour Minister John Senevinatne's compromise proposal for a wage of Rs 100, but it was rejected by the planter's association. ``Now that the strike has started, there is no going back on our minimum demand for Rs 105,'' he said, adding that the workers were not in effect asking for an increase in wage but compensation for the erosion in their income due to inflation.He said his being a cabinet minister could not prevent him from organising thestrike because he was a minister by virtue of being a trade union leader. ``I have established a convention as a minister of standing up for the workers' rights,'' he said and referred to the strike he had organised as a minister during the previous regime.A spokesman for the planters' association said they had decided to raise the wage unilaterally from Rs 83 to Rs 93 from January and also pay a ``price share bonus'' based on Colombo market price.