China's top quality supervision authority is making final preparations to implement a policy that will enhance warranties on private vehicles, officials said on Thursday.

"We are soliciting opinions and suggestions on guidelines to assess serious safety defects in private vehicles that were drafted by the defective-product administrative center under the General Administration of Quality Supervision, Inspection and Quarantine," Wu Xiaobo, an official in the administration's department of quality management, said at a news conference.

"The guidelines will help determine whether a private car has serious safety defects or not, and what kind of after-sales service the seller or manufacturer should provide to the consumer."