Mohammad Javad Haqshenas, a member of the pro-reform National Trust Party, called for opposition groups to join the political system.
"The political system, the rival grouping, and the pro-reform camp itself will suffer harm as a result of this absence," he was quoted by the semiofficial Mehr News Agency as saying. "Therefore, the ground should be prepared for the presence (of reformists) both in the pro-reform movement and in society."
His party was formed in 2005 by former Parliament Speaker Mehdi Karroubi. Karroubi and former Prime Minister Mir Hossein Mousavi challenged Iranian President Mahmoud Ahmadinejad in controversial 2009 elections. Both men are under house arrest.
Iranians staged a three-day boycott of milk and bread purchases to protest high food prices, The Wall Street Journal reports. Some bakers said their inventory was down more than 90 percent because of high prices.
A series of international sanctions targeting the Iranian energy sector have hurt the country's economy. Parliament Speaker Ali Larijani was quoted by the Journal as saying the country's "top priority is the economy."