Sri Lanka, one of the world's largest exporters of tea, is facing trade union action that could seriously undermine quality and quantity of the island's "green gold", officials said Monday.

Striking tea trade unions are expecting crucial talks later Monday to settle their wage demand, with their move coming at the start of the "quality" season for the island's main export commodity.

Lush tea plantations are getting

overgrown with some 400,000 workers keeping up a work stoppage for a seventh straight day Monday. They are demanding an 85 percent wage hike, trade union officials said.

Tea workers are currently paid 135 rupees (1.35 dollars) a day and they want it pushed to 250 (2.5

dollars). Employers argue that the take home pay of workers is already more than 250 rupees if allowances are taken into account.

Tea is Sri Lanka's main export commodity and earned 810 million

dollars last year as it shipped some 308 million of the 315 million kilograms it produced.

The employer's federation said the trade union action has cost the industry over three million dollars so far and the quality of tea would suffer unless the work stoppage ends immediately.

Sri Lanka is better known for its high quality aromatic tea that is made with tender leafs and buds of the plant which is botanically known as Camellia sinenis.