China's commerce ministry is investigating the takeover by General Motors of its former parts division Delphi.

Local carmakers and parts suppliers have expressed concern to the ministry that Delphi could discriminate against other customers in terms of price and product quality if the deal goes ahead.

Delphi wants the ministry to approve the takeover "as soon as possible", according to a report in Thursday's Beijing Times.

Delphi was spun off from GM 10 years ago and has been in bankruptcy protection since October 2005.

GM has agreed to buy Delphi's steering business and four US sites as part of a restructuring plan that allows creditors to take a controlling Delphi stake in exchange for US$3.4bn in debts.

The deal has been approved in the US and the EU but needs approval of other major markets including China before it can go ahead, according to the Beijing Times.

Delphi entered China in 1995 and supplies almost all local automakers including Chery, Geely and BAIC.