Iran's supreme leader has called for a review of the ban on thousands of candidates standing for elections.
Guardian Council members are chosen by Ayatollah Khamenei
Ayatollah Ali Khamenei urged the move at a meeting of the hardline Guardian Council, state television said.
The council disqualified more than 2,000 reformists from standing in February's parliamentary poll.
The ayatollah's intervention will be seen as a victory for the banned reformists who held a sit-in protest at parliament, correspondents say.
"The Guardian Council has enough time to review the cases carefully... to prevent the violation of anyone's rights," said Ayatollah Khamenei.
He went so far as to back the candidacies of the 83 deputies who have refused to leave the Iranian parliament, the Majlis, in protest at their being banned from standing for re-election.
"If their aptitude was proved in the past, the principle is that they are still competent unless it can be proved otherwise," he said.
But the supreme leader also said the council must not retreat in the face of people who wanted to resort to bullying tactics, a tacit reference to the protest itself.
The BBC's Jim Muir in Tehran says his careful words provided cover for the Guardian Council to think again and change its mind on at least some of the disqualifications without losing face.
Ayatollah Khamenei, who has the last word on all matters of state, had been keeping his distance from the controversy, urging both sides to exhaust all legal channels.
The 12-member Guardian Council - made up of clerics and Islamic lawyers - is empowered to ensure parliament's actions comply with Islamic principles.
Parliamentary Speaker Mehdi Karoubi has accused the council of trying to rig the outcome of February's election.
Reform-minded President Mohammad Khatami has promised to work to reverse the ruling but urged an end to the Majlis sit-in.
He told parliament it had been unjustly treated, and renewed his pledge to defend the rights of the people, and the principles of religious democracy.
President Khatami says he is trying to avert a crisis
He has threatened the resignation of his entire administration if the disqualification of reformist candidates is not lifted.
But MP Mohsen Armin vowed to continue the sit-in until the council backed down over the move.
"A meeting was held to discuss Khatami's proposal to end the sit-in," he said.
"All the protesting MPs... unanimously decided to continue the sit-in until we get solid results."
The Guardian Council has until 30 January to review appeals.
It is expected to approve at least some of the disqualified applicants, our correspondent says, but it remains to be seen whether that will satisfy the angry reformists.