The father of a female Saudi Arabian judo competitor, Wojdan Ali Seraj Abdulrahim Shaherkani says his daughter will pull out of the Olympics if she is not allowed to wear her hijab during bouts.
Sixteen years old Wojdan is due to compete in the +78kg category on Friday.
A Saudi official said earlier this month that its female athletes would have to obey Islamic dress codes.
But International Judo Federation president Marius Vizer said she would have to fight without the headscarf.
The sport has banned the headscarf for safety reasons and Vizer said last week: "The athlete from Saudi Arabia will fight in the spirit of judo and according to the principles of judo without a hijab".
Her father Ali told Saudi Arabia's al-Watan newspaper that his daughter "will not compete in the Judo Games on 3 August if the committee insists that she removes her hijab".
Olympic and Saudi officials are in talks with judo chiefs in order to find a solution but Mr Shaherkani told the newspaper he had not heard back from the International Olympic Committee on the matter.
Shaherkani and 800m runner Sarah Attar are Saudi Arabia's two female competitors.
There is almost no public tradition of women participating in sport in Saudi Arabia, and officials have found it difficult to find athletes who could meet the minimum qualifying standards.