An Iranian opposition leader who has been under house arrest since February has accused the Islamic establishment of intending to hold a rubber-stamp parliamentary election in March, his website Sahamnews reported on Monday.

Candidates began registering on Saturday for the March 2 vote, which will be the first litmus test of the clerical leadership's public standing since a disputed 2009 presidential vote that precipitated months of unrest.

Mehdi Karoubi was detained along with his wife, Fatemeh, when he urged supporters to gather for a Tehran rally in support of uprisings in the Arab world. His wife was later allowed out for medical treatment but he remains under house arrest.

Officials do not believe in the people's vote and they are preparing themselves for a rubber-stamp election, his wife quoted him as saying during their weekly meeting, according to Sahamnews.

Candidate registration will last one week and then entrants will be screened for their political and Islamic qualifications by the hard-line Guardian Council electoral watchdog.

The Council has stopped hundreds of reformist candidates in the past from participating in elections. A grandson of late revolutionary leader Ayatollah Ruhollah Khomeini was banned from running for a 2008 parliamentary vote by the Council.

The authorities want to repeat what they did in the 2009 presidential election by disqualifying the candidates.... and filling up the ballot boxes with counterfeit votes and creating an atmosphere of fear in the country, Karoubi's wife quoted him as saying, as reported by his website.

The 2009 election was followed by eight months of opposition protests that, while ultimately suppressed, pitched Iran into its deepest internal crisis since the Islamic Revolution and exposed divisions within the ruling elite.

The 73-year-old Karoubi and former prime minister Mirhossein Mousavi, who is also under house arrest with his wife, competed against President Mahmoud Ahmadinejad in the 2009 vote.

They became figureheads of the post-election protests by many who believed the vote was rigged to bring back President Mahmoud Ahmadinejad. Iranian authorities deny the charge and have portrayed the protests as a foreign-backed bid to undermine the Islamic government system.

Thousands of people, including senior reformers, were detained after the 2009 vote for fomenting unrest. Most of them have since been released, but more than 80 people have been jailed for up to 15 years and five have been sentenced to death.

Analysts say Ahmadinejad's allies want to secure a majority in the next parliamentary election to ease the way to winning the presidential vote in 2013.

Leading reformist politicians said pro-reform groups would not submit a separate list of candidates because the basic needs of a free and fair vote have not been fulfilled.

Authorities are concerned that a low turnout would question the establishment's legitimacy, and so hard-line conservative rulers have urged voters to participate in the March elections.

(Reporting by Mitra Amiri; Editing by Mark Heinrich)