Tehran (AFP) - Iran's long-sidelined reformist movement on Monday demanded a review after only one percent of its parliamentary election candidates were approved, prompting allegations turnout would suffer.

The vast rejection of candidates -- monitors said about 60 percent of more than 12,000 would-be MPs were barred -- could damage the credibility and legitimacy of the February 26 ballot, analysts said.

Those seeking to become lawmakers in Iran must first be screened by the Guardian Council, a conservative-dominated committee of clerics and jurists, before running.

The vetting procedure has been contentious for months, as the poll is an opportunity for reformists and moderate politicians to make gains against a currently dominant conservative camp in parliament.

On hearing of the rejections, reformists asked President Hassan Rouhani, a moderate cleric, to intervene and seek changes.

Rouhani is hoping his allies can capitalise in the elections after Saturday's implementation of Iran's nuclear deal with world powers lifted longstanding sanctions.

Ali Motahari, an outspoken conservative lawmaker, was among incumbents rejected this time round, media reported.

"Out of more than 12,000 registered candidates, 4,700 -- or about 40 percent -- were approved," Siamak Rah-Peyk, a spokesman for the Central Elections Supervising Committee was quoted as saying by state television.

Hossein Marashi, an official from the reformist camp, was quoted by the Shargh daily as saying that "out of over 3,000 reformist candidates across the country, only 30 have been approved -- only one percent."

"In Tehran, only four reformist candidates were approved," he said of the capital, where 30 lawmakers will be elected to the 290-seat parliament.

"We are supposed to present a list of 30 candidates. How are we supposed to do that with just four names?" Marashi added.

The Reformists' High Council for Elections called for the Guardian Council to revise its decision.

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- Appeals expected -

"We are concerned that such a trend of extensive rejections of reformist and pro-government candidates might lead to people's reduced participation in the elections," it said in a statement, according to the official IRNA news agency.

"We expect the Guardian Council to... revise the disqualifications and we ask the president -- in charge of implementing the constitution -- to interact with decision-makers and act to fix the current problem."

The ISNA news agency Monday quoted Elham Aminzadeh, the vice president for legal affairs, as saying Rouhani would "negotiate" with the Guardian Council "to defend the rights of the rejected (candidates) in case mistakes were made".

Rouhani is aiming to accelerate political and social reforms he promised before being elected in 2013, an outcome more likely if there are fewer hardline conservatives in parliament to block his legislation.

Applicants can appeal their rejection and the council will publish a final list of vetted candidates on February 4.

Those rejected included some with criminal convictions and others who submitted incomplete documents, said Rah-Peyk.

However, Saeed Laylaz, a political analyst close to the reformist camp, said he was hopeful there would be a rethink and that many more candidates would be approved on the final list, possibly more than 100.

"The game is not over yet," he told AFP. "We expected rejections from the Guardian Council. But I am hopeful that there will be a solution as these rejections represent a risk to the credibility of the election."

The parliamentary polls coincide with the election of Iran's highest clerical body, the Assembly of Experts, a powerful committee which monitors the work of Iran's supreme leader.

However its more important task -- 88 members will be elected to eight-year terms -- is likely to be selecting a replacement for the incumbent, Ayatollah Ali Khamenei, 76, if he dies during the next assembly's tenure.

In 2012, 62 percent of nearly 5,300 registered candidates for the parliamentary elections were approved.

Reformists did not actively participate in the polls at the time, having disputed the result of a presidential election three years earlier that saw Mahmoud Ahmadinejad returned to office.

The decision to stay away four years ago left the reformist camp ravaged, with few MPs in parliament. Since Rouhani's election in 2013, however, the movement has regrouped.