Quality regulators in China have asked Volkswagen to provide technical documents following the company's recall of almost 600,000 vehicles - the first time the agency acted since a law mandating timely safety campaigns came into force.

China's General Administration of Quality Supervision, Inspection and Quarantine asked for the documents following last month's recall of Sagitar and Beetle models. VW issued the recall two months after the quality inspector started investigating complaints from owners over broken rear suspension axles.

Laws introduced last year give the government powers to order investigations and impose fines should manufacturers and importers fail to recall faulty vehicles in good time.

The request to VW is the first time the regulator has asked a carmaker for documentation on a recall since the safety law took effect. A spokesman for the company said that VW is in discussions.

Some customers have held demonstrations outside VW dealerships over the suspension issue. AQSIQ said on its website that it takes the consumer reaction to the Volkswagen recall very seriously.

VW Group China president and CEO Jochem Heizmann said the Sagitar sedan is safe and the company is offering free inspection and modification of the axle using metal plates.

VW said the safety problem occurred when a car was involved in a rear-end collision. The axle was damaged but the driver did not notice it. An investigation launched by the company discovered that the torsion crank broke after the driver continued to drive it without getting it repaired.

Earlier Sagitar models involved in the rear axle issue use coupling type rear suspension while the latest 2014 New Sagitar does not appear to face the same issue so far. The new model uses multi-link independent rear suspension, the same as the New Jetta model in North America and Europe.

The carmaker is recalling 581,090 New Sagitar and Beetles to fix metal plates to the rear torsion crank axle for modification, which will stabilise the vehicles and emit warning in case of cracks.

It has offered to replace the 55 cases of broken axles due to a rear or side collision it has identified in its investigation, adding that the cars are safe and will not have issues if they have not been involved in collisions.