Toyota's global output, which currently stands at roughly 9.89m units, is not expected to surpass 10m units in fiscal 2012.

The main reason for this is slowing economic growth in China, the Nikkei reported, noting it was a disappointment for Toyota which had hoped to become the first global automaker to produce more than 10m units in a single year.

The firm's foreign rivals, meanwhile, have been racing to take advantage of Toyota's unimpressive sales in China this year. Volkswagen's global sales rose more than 10% throughout the January-September period, primarily due to its strong performance in China. Its sales in the country rose nearly 20% over the same period, mainly due to the popularity of the Passat sedan, one of its core models.

GM, meanwhile, reopened a factory in Tennessee this year to produce sport utility vehicles. This has helped to drive up its North American output for the year by 12%.

The US carmaker also plans to increase its investments in China. It started building a new factory in Wuhan, Hubei Province, to connect its operations in China's inland and coastal cities by using the Chang River as a transport route. It wants to eventually turn the Wuhan factory into a hub to produce vehicles for sale in the nation's interior cities, where income levels are generally lower than along China's eastern coast.

However, the fallout from the European sovereign debt crisis has continued to pose problems for Toyota's European and US competitors. Volkswagen's sales in Europe fell 3% during the January-September period, contributing to an operating profit decline of 10%. Over the same period, Volkswagen's subsidiary, SEAT, recorded a loss of approximately EUR100m euros (US$127m).

Combined, Toyota's group companies sold 7.4m cars throughout the world during the January-September period, for an increase of 28% on the year. GM's global group sales reached 6.95m units over the same period, up 3% on the year, while Volkswagen sold 6.86m cars, up 11% on the year.

For now, Toyota continues to maintain its edge over its global rivals. However, its long-term outlook is less certain, as its competitors are more than willing to catch up.