Kamann boss Bernd Lieberoth-Leden is considering building up its north American business, Automobilwoche said.

The independent vehicle assembler and cabrio specialist is currently starting up a new plant in Plymouth, Michigan to assemble the Pontiac G6 Cabrio steel folding roof system, also developed by Karmann.

Karmann has invested $US15 million in Karmann Manufacturing LLC which will this summer start production by assembling up to 30,000 roof systems a year.

For Lieberoth-Leden the General Motors roof system is just a beginning, Automobilwoche reported.

The Plymouth plant should also be able to fulfil a possible project for Chrysler - apparently for the successor to the Chrysler Sebring.

Lieberoth-Leden is not ruling out complete vehicle assembly in the USA.