HONG KONG  Hostility from Chinese regulators and financing problems are increasingly likely to scuttle plans by an obscure Chinese machinery company to buy the Hummer division from General Motors, people close to the negotiations said on Tuesday.

General Motors has already extended repeatedly its deadline for completing the deal, with the current deadline at the end of this week; the original deadline was last September. But the buyer, the Sichuan Tengzhong Heavy Industrial Machinery Company, has failed to win regulatory approval for the deal at a time when senior Chinese officials are trying to put a new emphasis on limiting China’s dependence on imported oil and protecting the environment.

Chinese banks are now pulling back from offers to lend money to Tengzhong for the deal and Western banks are leery of becoming involved, people close to the transaction said. Auto industry analysts are deeply skeptical the deal will be completed.

“The deal is on the ropes, if it’s not on the canvas yet,” said Michael Dunne, the president of Dunne & Company, a Hong Kong auto consulting firm.