Seddigh, 29, became a feminist icon when she won the title, but was walking towards her Peugeot 206 at Tehran's Azadi stadium when stewards blocked her way, citing "security problems".
The snub followed days of wrangling with Iran's racing federation over her right to take part in an event she won two years ago on her way to becoming national champion.
According to press reports yesterday, in the lead-up to the race she was told her participation was not guaranteed but was advised to register her name. Her registration was passed after technicians gave her car the all-clear, the report said.
"I thought I had been given the go-ahead," she said.
It was the first time Seddigh, whose exploits earned her the nickname "the little Schumacher", had been excluded from a contest. Senior federation officials said they had been unable to obtain permission for her participation.
However, Seddigh believes she was banned to prevent her earning enough points to repeat her championship success, which won her international fame but upset Iran's male-dominated religious ruling establishment.
Seddigh says a Muslim cleric has already issued a fatwa - a legally binding religious ruling - stating that there is no religious bar to women racing against men provided Islamic dress code is observed.
The federation's vice-president, Hossein Shahryari, said Seddigh had been barred because of a decree restricting women to female-only events. That decree has now been lifted, he said.
But he added: "Women are speaking highly of themselves and that causes men who sacrifice their lives in this sport disappointment. Women are not champions in this sport, they are only participants. If they observed Islamic regulations more they would not have such problems."
Source: Sydney Morning Herald