Foreign auto makers will out-produce the Detroit Three in North America by 2012, meaning even more changes are coming for struggling auto suppliers, said auditing firm Grant Thornton LLP in a new reporting looking at suppliers.

As such, the company says suppliers will need to increasingly sell themselves to European- and Asian-based auto makers while the auto-supply industry shakes out from necessary consolidation and deleveraging.

Grant Thornton said many suppliers may need to use bankruptcy to fix their balance sheets - some have already begun to do so - while ensuring they are well-diversified on a customer, geographic and product basis.

The report comes after months of production cuts by global auto makers who have been battered by sharply contracting demand for new cars as consumer confidence waned and credit markets turned sour amid the financial crisis. Suppliers which are strongly dependent on Detroit have suffered along with those auto makers. But some analysts now see auto-production rates picking up in the second half of the year - albeit slowly, as economic woes persist.

By 2012, General Motors Corp. (GMGMQ), Ford Motor Co. (F) and Chrysler Group LLC are expected to have their North America assembly capacity reduced to 7.5 million units, down 35% from 2008. All other auto makers combined will increase capacity by about 20% in the region to more than eight million units.

German auto makers Volkswagen AG (VLKAY) and BMW AG (BMW.XE) have announced plans to double their combined capacity in North America - that would add 500,000 potential vehicles. Meanwhile, Toyota Motor Corp. (TMC), Honda Motor Co. (HMC), Nissan Motor Co. (NSANY) and Hyundai Motor Co. (005380.SE) will expand their combined capacity by 20%, or nearly one million units.

Capacity use in North America should approach 90%, up from the 75% historical rate, assuming an annual sales rate of 15 million units in the U.S. for 2012. This year's depressed sales rate is expected to be about 10 million.

"In light of the dramatic restructurings that will occur over the next several years, North American suppliers have important strategic decisions to make, and the strategy must be defined and implemented quickly," said Kimberly Rodriguez, co-leader of Grant Thornton's automotive practice.

-By Mike Barris, Dow Jones Newswires; 201-938-5658; mike.barris@dowjones.com