FRANKFURT (Reuters) - General Motors' <GM.N> ailing European brand Opel believes there is significant potential to cut costs in manufacturing cars by using materials different from its parent, Opel's interim chief executive told a German newspaper.

"GM has global requirements for parts and components that are unusual in the industry. A starter is tested at 40 degrees below zero, just as would be needed in Alaska, otherwise it fails the test," Thomas Sedran told the Tagesspiegel in comments published on Friday.

"The supplier can only meet these if he uses expensive materials."

(Reporting By Christiaan Hetzner)