That may be easier than jumping through a number of domestic regulatory hoops, including the approval of the Ministry of Commerce, the National Development and Reform Commission and the Ministry of Industry and Information Technology.

Tengzhong, which is said to have connections with military officials in Chengdu where the company is based, appears to be failing in its efforts to persuade the central government to approve the Hummer acquisition, said a person with direct knowledge of the deal. Beijing fears the move by the low-profile construction company to acquire the gas-guzzling Hummer goes against its policy of building an environmentally-friendly auto sector.

'Tengzhong did not do pre-lobbying of the central government when it decided to purchase Hummer,' the person said. 'Beijing only knows there was such a deal after the announcement by the company last June.'

Jia Xinguang, an industry analyst, said even if Tengzhong goes offshore it will still need to seek government approval if it wants to import the vehicles into China. If the government says no, the company will lose access to the huge mainland market.

Little-known Tengzhong said early this month that it and GM had agreed to push back the deal deadline from January 31 to the end of February as they seek approval from mainland regulators.

Suolang Duoji, a major shareholder of Tengzhong who is regarded as the architect of the deal, said earlier this month he hoped the US$150 million deal can be approved by regulators this spring.

Both Tengzhong and GM signed a definitive agreement in October but the deal had been intensively questioned.

State media including Xinhua, China Daily and People's Daily noted that the acquisition runs counter to the national policy of a 'green' auto sector.

The cold shoulder given to the Hummer deal contrasts with the support provided by the Ministry of Commerce to Geely Holding Group's acquisition of Ford Motor's Volvo unit.

In June, mainland media reported the NDRC was concerned Hummer's lack of green credentials clashed with Beijing's aspirations to clean up the environment.

The NDRC was also concerned that Tengzhong, a small construction machinery maker, lacked the expertise to run a major car brand.

In September, the Ministry of Commerce returned Tengzhong's application to buy Hummer to the company, asking for more information.

Besides Tengzhong, other domestic carmakers like Geely and Beijing Automotive Industry Holding have joined the race to acquire global auto assets.

Beijing Auto spent US$200 million to buy the intellectual property behind Swedish firm Saab's 9-3 and 9-5 executive sedans and some tooling equipment.

Bumpy road

A major shareholder is hoping the deal can be approved this spring

Tengzhong and GM have signed a definitive agreement for the Hummer acquisition valued at, in US$: $150m