INDIA'S top carmaker Maruti Suzuki has suspended production at a plant near New Delhi after a manager was burned to death and scores of others injured in a riot by angry workers.

Maruti identified the dead man as the plant's personnel manager, Avnish Kumar Dev, whose charred body was found after the rampage late on Wednesday during which supervisors were attacked and offices set on fire.

"We are deeply disturbed by the mob violence," Maruti said in a statement that praised Mr Dev as "deeply committed to cordial industrial relations" at the Manesar plant 50km from the capital.

Maruti shares plunged nearly 9 per cent to 1117.35 rupees ($19.46) on investor fears of a lengthy shutdown. Last year, the company's operations were crippled by a long dispute over pay and union recognition.

The carmaker, owned by Japan's Suzuki Motor, said the plant's offices were "burnt beyond repair" while nearly 100 of its managers had to be hospitalised, some with serious injuries.

The workers, some wielding iron rods, fanned out in groups, beating managers "on their head, legs and back, rendering many of their victims bleeding and unconscious", the company said.

A number suffered broken bones, head wounds and other injuries, a Maruti executive said, while two Japanese executives, including the Manesar plant manager, were also in hospital with undisclosed injuries.

Maruti, which makes 550,000 vehicles a year at the plant - accounting for a third of its output - said it would announce its decision shortly "on the next steps with regard to resuming operations".

"This is the most serious labour unrest I have seen in the last few years," Deepesh Rathore, managing director of IHS Automotive India, a consultancy, said.

"The situation is so ugly that senior managers may not want to work with Maruti at the plant in future, fearing for their safety."

The violence suggests "there was always a very strong undercurrent of discontent" even after work resumed at the plant last year, he added.

Deputy police commissioner Maheshwar Dayal said at least 88 workers had been arrested and faced possible charges from murder to rioting and arson.

"All senior employees had to run to escape the angry mob - some jumped over factory walls," Virendra Prasad, a supervisor who suffered head injuries, told reporters.

Maruti said the dispute erupted Wednesday morning when a shop-floor employee beat up a supervisor. It accused the workers' union of stopping managers from taking disciplinary action and blocking them from leaving the plant.

"By any account, this is not an 'industrial relations' problem in the nature of management-worker differences over issues of wages or working conditions," said Maruti, calling the violence "unprovoked and gruesome".

The union gave a different account, saying the supervisor "abused" a worker belonging to India's lowest social caste who was suspended after he complained.

When efforts to resolve the row were under way, Maruti called in "hundreds of bouncers on its payroll to attack the workers... to corner us into submission", said Ram Meher, head of the Maruti Suzuki Workers Union.

The Manesar plant employs 2000 people and produces Maruti's top-selling Swift and A-Star hatchbacks and SX4 sedans.

An extended closure would be a big blow for Maruti, whose profits slid 29 per cent last year on the back of labour disputes and a slowdown in Asia's third-largest auto market.

Maruti has another plant in the Delhi area whose operations were unaffected by the latest strife.

It plans to build a new factory in western Gujarat state which is emerging as a new car-producing hub following investments by Ford and Indian vehicle-maker Tata Motors.

