Iranian authorities will crack down this week on any public protest against the year-long house arrest of opposition leaders, Mirhossein Mousavi and Mehdi Karoubi, an official was quoted as saying on Sunday.
Iran, at odds with the West over its disputed nuclear programme, holds a parliamentary election on March 2, its first national poll since Mousavi and Karoubi were beaten by President Mahmoud Ahmadinejad in a 2009 vote they said was rigged.
The government denied any fraud in the election, which ignited eight months of street protests, prompting a violent state response and deep splits in the ruling establishment.
The two leaders were placed under house arrest on Feb. 14 last year after they urged their supporters to join a rally in support of popular uprisings across the Arab world.
Tehran provincial governor Morteza Tamaddon said a call by reformists for a rally on Wednesday to mark the anniversary of the curbs imposed on Mousavi and Karoubi was a "publicity stunt" by opponents of Iran's Islamic revolution.
"We will confront such moves with full preparation and all kinds of security apparatus," the reformist Kaleme website quoted Tamaddon as saying.
Tens of thousands of Iranians joined state-organised rallies on Saturday to mark the 33rd anniversary of Iran's revolution.
The parliamentary election, now less than three weeks away, will test the popularity of Ahmadinejad's supporters and those who back the supreme leader, Ayatollah Ali Khamenei, in a power struggle between conservative factions.
Reformists have said they are boycotting the election as their demands for a "free and just" vote have not been met.
A low turnout would hurt the leadership's efforts to contain the damage to its legitimacy caused by the 2009 election and the forcible suppression of the opposition "Green" movement.
Dozens of people were killed and thousands arrested during the post-election unrest that engulfed major towns and cities in the worst political upheaval in the Islamic Republic's history.