India's Tata Motors insisted it would stick to its planned schedule for the high-profile rollout of the world's cheapest car despite months of protests over a land dispute.

The vehicle giant began moving machinery and equipment from a nearly completed factory in West Bengal state on Wednesday after violent demonstrations halted construction on the site slated to produce the Nano.

'The Nano car will roll out during the last quarter of the calendar year between October and December as promised,' a senior Tata Motors official said.

The firm has said it will try to launch the car, slated to cost 100,000 rupees ($2,150) as near to next month's big-spending Hindu festival season as possible.

The official would not say where the Nano - dubbed the 'People's Car' and aimed at making automobile transport affordable to ordinary Indians - would be built except it would be at 'one of our existing manufacturing facilities'.

The 90 per cent built Singur plant, which has emerged as a symbol of the clashing interests of India's farmers and industry, could not be a production site 'unless there is a congenial atmosphere,' he said.

That possibility appeared more remote after attackers on Monday beat up two security guards at the plant.

It was the latest in string of violent incidents at the site by protesters, who claim farmers were forced by the Marxist state government to give up their land for a pittance so the plant could be built.

Tata Motors would not say when it might decide the ultimate fate of the Singur plant, into which it has poured $350 million.

Shifting the project could cost $50m to $100m, according to industry estimates. But a company source said: 'It is a decision we will make very soon.'

Trade lobbies say the problems were a blow to India's efforts to woo foreign investment.