President Hassan Rouhani said the parliament is supposed to represent all segments of the society rather than a particular faction.
The president was speaking after the publication of a list of candidates approved to stand in the upcoming parliamentary vote.
About 12,000 candidates signed up for the next parliamentary election due on February 26. The Guardians Council, a clerical body in charge of vetting the candidates on technical and ideological grounds, has reportedly disqualified an overwhelming number of the registered reformists. "Parliament is the house of the nation, not a single faction," Rouhani said, adding that as the Leader of the Islamic Revolution Ayatollah Seyyed Ali Khamenei has stressed "the vetting must be based on the law, not [one's own] preferences".
"If only one faction, and not others, is allowed to run for parliament, holding elections would be pointless," he was quoted as saying by IRNA.
Addressing a gathering of provincial officials in Tehran on Thursday, the president said he has assigned Vice President Es'haq Jahangiri to discuss the disqualifications with the Guardians Council.
"The forthcoming vote should be a display of impartiality, non-interference, commitment to the law, a great sense of security and healthy competition."
Rouhani noted that complicated international and regional situations and problems facing the country have made it more crucial than ever to ensure that the most qualified candidates enter the parliament.
"Let's all try to help create a competitive and promising atmosphere so as to witness a huge turnout because the country belongs to all the people and every group, faction and segment of the population should be represented in 'the house of the nation'," he said.
The president said the Islamic Republic managed to achieve its objectives in the July 14 nuclear deal with major powers, thanks to the negotiators who asserted Iran's right by demanding all along that all sanctions must be removed immediately under any deal.
Rouhani said the accord was the outcome of "30 months of difficult negotiations and tough and major decisions … and at least on three occasions, I ordered [the negotiators] to pull out of the talks because they [the other side] refused to accept" Iran's demands.
