Security officials carried out the arrests late on Saturday in the Nile Delta province of Beheira, detaining former MP Gamal Heshmat as part of the group, Mohammed Habib said.
While members of his Islamist group are periodically detained, Habib believes the latest wave could be linked to next year's parliamentary elections in which the Brotherhood is planning to run.
"This is another attempt by the authorities to distance the Muslim Brotherhood from Egyptian political life," Habib said.
"Right now we have no less than 250 members in jails. Some are being held while on trial, some are in preventative detention, some are in jail," he said.
In 2005, the Muslim Brotherhood, the largest and most organised opposition group in the country, won 88 seats out of 454 in parliamentary elections marred by violence.
The group is officially banned but fielded candidates as "independents."
Muslim Brotherhood members are left to operate openly by the authorities and even have a working office in central Cairo, but the group is subject to regular crackdowns.
Source: Asharq Alawsat