Unlike the Zonda, the Huayra was developed to meet US safety and emissions regulations. Pagani said it would need to spend $7 million to develop an advanced airbag programme and would lose $8 million in profits if the waiver were denied.
Now the Huayra's appearance in the US may be delayed until 2015. The Huayra was unveiled at the Geneva motor show in March.
Company founder Horacio Pagani said there was much interest from North American buyers in his products but, unlike other supercar makers, he was in no rush to expand too quickly.
"At the time, the production capacity was not enough to fulfil all the demand inquiries that we got from our worldwide customers," he said.
"The customers for these very special high-end cars are very sophisticated, and when they come to Pagani they have to get not just a supercar, but super attention and service together with the car.
"It's not easy to properly look after each of them, so this is why, step by step, we are developing new markets just to make sure that every new customer coming into the Pagani family is very well looked after and pampered by our staff and to meet every request."
Horacio said that that existing customers need to be attended to before orders from new markets could be handled. "Pagani plans to enter the US market only at the end of the 2012," he said. "We already have a huge demand for the car from our existing market, which is outside North America. We have to allow for some time for Pagani to fulfil the demand of existing customers and then start with our new ones."
Latest reports say Pagani appears to have been prepared for the Traffic Safety Administration's refusal. It began work three years ago on the advanced airbags, expecting the safety authority to turn down its application for a continued exemption. At worst, planned deliveries of the Huayra to the US could be pushed back to early 2013.