Buoyed by the encouraging response to its premium mid-size car Chevrolet Optra, General Motors India is launching an automatic transmission variant of the vehicle by early next month, sources said.

The car would have the same 1800cc engine, which powers the existing manual transmission model, the sources told PTI.

The new variant is expected to be priced Rs 50,000-Rs 60,000 more than the three manual transmission versions -- base, premium and luxury -- which cost Rs 789,000 , Rs 849,000 and Rs 969,000 respectively.

When contacted, GMI vice president (corporate affairs) P Balendran confirmed that the company was planning to launch an automatic version of the Optra.

He declined to give details.

GMI, a wholly-owned subsidiary of leading US automaker General Motors Corporation, has sold 1,875 units of the car since its launch in early July.

The company plans to nearly double its total car sales to 18,000 units this year, of which the Optra is expected to contribute 10,000-12,000 units.

The Optra is the second product to be introduced by GMI after the sports-utility-vehicle Chevrolet Forester as part of plans to grow its sales over five-fold to about 50,000 cars in the next three years.

It competes in the emerging D1 segment against cars like Skoda Octavia and Toyota Corolla.

The Optra, which is produced at GMI's plant in Halol (Gujarat), has been developed on a new platform, designed by GM Daewoo Automotive Technology (GM-DAT) of South Korea while the engine has been sourced from GM's Australian subsidiary, Holden.

Production at the plant has been increased to 104 cars in two shifts, the sources said, adding that the company might start a third shift if demand increases further.

GMI also makes the mid-size car Opel Corsa as well station wagon Opel Corsa Swing and hatchback model Corsa Sail.