General Motors CEO Dan Akerson smiles while sitting in a GM automobile outside of the New York Stock Exchange, Nov 18, 2010. [Agencies]

General Motors Co regained its title as the world's top-selling automaker from Japanese rival Toyota Motor Corp in 2011, but the US company faces a challenge to stay on top this year as Toyota rebuilds its disaster-struck business.

GM, bouncing back from bankruptcy less than three years ago, said on Jan 19 it sold 9.026 million vehicles globally last year, up 7.6 percent from 2010, with its Chevrolet brand setting a sales record of 4.76 million vehicles.

The Detroit-based automaker's return to the top slot comes after its 2009 taxpayer-funded bankruptcy restructuring allowed it to cut its spiraling legacy costs.

It also comes as Toyota's sales fell an estimated 6 percent in 2011 to 7.9 million vehicles, hit by severe production cuts following an earthquake, tsunami and nuclear crisis in Japan and deadly floods in Thailand.

The Japanese automaker is ramping up production to rebuild depleted inventory and will add output capacity in emerging markets such as Brazil and China this year. But analysts said it also faced stiffer competition as rivals step up their game.

"Toyota's biggest problem is that even without the natural disasters, its sales weren't exactly growing," JP Morgan auto analyst Kohei Takahashi said.

"The ranking is not that important, but they need a convincing strategy to boost their sales," he said, adding that Toyota was behind rivals such as Nissan Motor Co in rolling out small cars for emerging markets.

Toyota has lagged the sharper sales growth at rivals such as Nissan and Hyundai Motor Co because of a relatively slow push into emerging markets as it scrambled to meet runaway demand in mature markets in the past decade.

In a bid to catch up, Toyota is adding factories in Brazil, China, Thailand and elsewhere, aiming to sell half its cars in emerging markets by 2015, up from around 40 percent now.

Bumps in the road

Toyota's 2011 worldwide sales tally included listed subsidiaries Daihatsu Motors Co and Hino Motors Ltd, and it put the carmaker behind Volkswagen AG, which sold 8.16 million vehicles last year.

It also just trailed the 8.03 million sold by Renault SA and partner Nissan, though this number includes the 638,000 cars sold by Russia's AvtoVAZ, in which the French car maker owns a minority 25 percent.

Excluding AvtoVAZ, Toyota remained ahead.

Toyota gave no forecast for this year for the group, but said it expected parent-only sales to jump 20 percent to a record 8.48 million vehicles in 2012. Daihatsu and Hino sold around 850,000 vehicles combined in 2011.

Toyota, due to publish its final sales tally for 2011 later this month, was once the envy of the auto industry.

It has had a torrid couple of years: a quality crisis that triggered the recall of more than 10 million vehicles globally, a tarnished image and a subsequent slide in sales.

Just as it was recovering from that, the March 11 quake and tsunami devastated Japan's northeastern coastline, forcing it and other domestic automakers to scale back output for months. And in October, damage to suppliers from Thailand's floods delivered a further setback to their recovery.

On top of that, a strong yen is hurting profits on vehicles shipped from Japan and has prompted it to look at turning its North American operations into a big exporter.

South Korean sister carmakers Hyundai Motor Co and its 34 percent owned Kia Motors Corp racked up total sales of 6.53 million last year.