General Motors GM.UL is examining ways to ramp up production of four newer models that are selling well above its expectations, a GM spokesman said on Wednesday.

All four models are greatly revamped from previous versions and one, the Chevrolet Camaro, was resurrected five months ago after being out of production for seven years.

The four models are the Chevrolet Equinox, a crossover utility vehicle; Buick LaCrosse, a sedan; Cadillac SRX, also a crossover; and the Camaro, a sports car.

The potential increase in production at GM could prompt more workers to be recalled from layoff, a rare bright spot for the world's No. 2 automaker just two months after it emerged from bankruptcy protection.

GM spokesman Tom Wilkinson said GM knew it would have to increase production of some of its models after a summer when inventory levels were at unsustainably low levels, but that these four models in particular had outstripped expectations.

GM said it will also look for a second production plant for the Equinox, which is now assembled at the CAMI Automotive plant in Ingersoll, Ontario, which GM owns with Suzuki Motor (7269.T). The Terrain is also built there.

Sales for the 2010 model Equinox were about 9,900 through Sept. 15. The redesigned Equinox was launched in June.

Trade journal Automotive News reported on Tuesday that to increase production of the increase production of the Equinox GM would add a third shift to the Ontario plant in October.

GM and other automakers expect much fewer sales in September after the $3 billion Cash for Clunkers federal incentive program ended about three weeks ago.

GM sales in the United States are down 35 percent so far in 2009, and it has lost two percentage points of market share.

Industry-wide 2009 U.S. auto sales are expected to be near 10 million vehicles, down from 13.2 million vehicles in 2008.

GM this week began an aggressive marketing campaign aimed at overcoming public perception that it makes inferior cars.

Part of that campaign is a 60-day, money-back guarantee. (Reporting by Bernie Woodall; editing by Gunna Dickson)