Fifty Iranian filmmakers and artists, in a signed letter released on Tuesday, urged the authorities to release Panahi, a news agency reported.
"Ever since he was apprehended, I have managed to talk to him twice. I went to Evin to meet him last Thursday, but was not allowed to meet," Tahereh Saeedi said of the Tehran jail where her husband is being held.
Media reports have said Panahi was arrested for making a film about the unrest which rocked the Islamic republic after last year's disputed re-election of President Mahmoud Ahmadinejad.
But his wife denied these reports, saying "the film was being shot inside the house and had nothing to do with the regime."
Saeedi also said that the authorities had still not filed any charges against her husband.
"I spoke to (Tehran prosecutor Abbas Jafari) Dolatabadi yesterday, but he did not give me any precise answer. But I sensed that he has a positive approach to the case."
According to opposition websites, Panahi was arrested along with 16 other people, including Saeedi and the couple's daughter and six human rights activists. Fourteen of those detained have been freed so far.
Panahi, a vocal backer of the opposition movement, was arrested when security forces raided his Tehran home on March 1.
Soon afterwards, Dolatabadi said Panahi was not arrested for political reasons or because he is an artist. He was "accused of some crimes and arrested with another person following an order by a judge."
Panahi, 49, is known for his gritty, socially critical movies such as "The Circle," which bagged the 2000 Venice Golden Lion award, "Crimson Gold" and "Offside," winner of the 2006 Silver Bear at the Berlin film festival.
In February, the authorities banned Panahi from leaving the country to attend the Berlin film festival.
In a signed letter released by the ILNA news agency on Tuesday, 50 Iranian filmmakers and artists called for Panahi to be set free.
They said the country's film industry has been Iran's "cultural ambassador and representative to the world over the past 30 years since the Islamic revolution."
"We ask the ministry of culture, intelligence and head of judiciary to take measures to release" Panahi, the letter said.
