The subject of foreign automakers claiming Chinese companies are copying their designs has reared its head again.

According to the Financial Times (FT), DaimlerChrysler and BMW are both threatening legal action over Chinese-made vehicles that they claim are copies of their own models.

The paper said German chancellor Angela Merkel on Tuesday described plagiarism and copyright infringement in China as "a big problem" in a speech in Beijing.

DaimlerChrysler told the paper it would consider unspecified legal action if Shuanghuan Automobile showed the Noble, which it says closely resembles its Smart Fortwo city car, at next month's Frankfurt motor show.

"If suddenly a car turns up that looks like a Smart but isn't one, but rather a copy produced by not entirely legal means, then that's not good," Ms Merkel was quoted as saying.

"We take intellectual property protection very seriously," DaimlerChrysler told the FT. "We decided to reserve the right to pursue legal action."

BMW was reported to have said it was considering legal action against the importer of the Shuanghuan vehicle CEO - which it claims closely resembles the previous-generation X5 SUV replaced by the current model in 2006.

The Financial Times added that DaimlerChrysler had not detailed its legal plans but was understood to have contacted Shuanghuan about the issue.

The paper noted that DC last year stopped Chinese automaker CMEC from selling another vehicle that closely resembled the Smart.

Toyota told the paper that another Chinese-built vehicle, the Zhejiang Jonway UFO, resembles the previous generation RAV4 SUV but added it decided not to take legal action when it became aware of the UFO in 2005.

In November 2005, China's Chery and General Motors finally settled a long-running dispute in which the US-owned automaker claimed the Chinese firm's QQ city car was a copy of the GM-Daewoo-designed model sold in China as the Chevrolet Spark. Details of the settlement were not released.

GM also had threatened legal action against Chery because it claimed 'Chery' sounded too much like 'Chevy', the nickname for the Chevrolet brand.

Chery agreed in September 2005 that it wouldn't market its vehicles under its own name in the United States - it has since gone on to forge a deal with Chrysler to supply small cars to the US and other markets using that automaker's own brand names.