She said members of the religious-nationalist alliance have been holding this regular meeting for more than a decade.
Security forces in Iran have arrested more than 30 opposition activists who were attending a meeting in the capital, Tehran.
They were members of a moderate opposition group known as the religious-nationalist alliance, which supports the reform policies of the Iranian President, Mohammad Khatami.
The arrests on Sunday evening came only a few hours after President Khatami told the Iranian parliament that democracy was the only way forward in the Islamic Republic.
Security forces raided the home of an opposition activist, Mohammad Baste-Negar, and detained about 35 people.
'No reason' given
The wife of Ahmad Zeid-Abadi told the BBC that no reason had been given for the arrest of her husband and his associates.
She said members of the religious-nationalist alliance have been holding this regular meeting for more than a decade.
The group is popular with some sections of the middle classes and it supports President Khatami's reforms.
Conservative-controlled courts have jailed some other members of this group in recent months, including the veteran dissident figure, Ezzatollah Sahabi.
There are reports that Sunday evening's meeting had been called to celebrate the release of Mr Zeid-Abadi from prison.
Politician and educator
Others arrested include Ali-Reza Rajaei, who won a seat in parliamentary elections last year, but was later disqualified by a conservative-run election supervisory body.
A former chancellor of Tehran University, Mohammad Malaki, is also among those taken away by security forces, apparently on the orders of the revolutionary court.
The families of the detainees gathered in front of the court in Tehran on Monday morning in an attempt to gain more information about their whereabouts. They later went to the Iranian parliament to continue their protest.
The deputy speaker of parliament raised the issue in the open session of the assembly and said that it was questionable that these people had been arrested on the eve of President Khatami's landmark visit to Russia.