Tehran (AFP) - Iranians got a first taste Thursday of the campaign for next week's elections, pitting reformists and moderates against conservatives in polls that could shape the country's future over the next decade.

Voters will take part in two ballots -- one to elect members of parliament and another to pick the Assembly of Experts, a powerful committee of 88 clerics who supervise the work of supreme leader Ayatollah Ali Khamenei, Iran's ultimate authority.

But the run-up to voting day on February 26 has been dominated by controversy over who will be allowed to contest the elections rather than actual debate of the policies that candidates support.

All those seeking public office in Iran are vetted for their loyalty to the Islamic republic and almost half the applicants seeking to become lawmakers were excluded.

In the initial round of vetting, reformists suffered the heaviest blow, with thousands of candidates being rejected.

That decision -- taken by the Guardian Council, a constitutional watchdog with veto power over who can stand -- was criticised by Hassan Rouhani, Iran's moderate president whose nuclear deal with world powers stands to open Iran up to the West.

After he and government ministers intervened an extra 1,500 candidates were allowed to run. But grievances remain, particularly because of the exclusion of many prominent reformists.

A pro-Rouhani coalition of reformists and moderates is playing up the nuclear agreement's long-term economic potential and is seeking to swing the balance of power in parliament away from conservatives.

Should the bloc -- the Alliance of Reformists and Government Supporters -- succeed, Rouhani may be able to pass legislation that delivers at least modest political changes and social reforms.

Referring to the group's campaign slogan "Second Step", Mohammad Reza Aref, its number one candidate, told AFP the first step had been Rouhani's election victory in 2013.

"That approach won and we want to continue that approach now in these elections," said Aref, whose decision to stand aside three years ago helped Rouhani to a landslide victory.

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Emphasising the regime's tight control of elections, applications and vetting procedures took seven weeks while official campaigning for parliament will last just seven days.

Ruhollah Salahshoori, a canvasser at the downtown Tehran event where candidates from the Aref-Rouhani slate appeared, said the elections "must bring about a fundamental change".

- May pick next supreme leader -

"I'd like us to make a step forward the same way our government and foreign minister did," the 36-year-old engineer said, referring to the historic nuclear agreement that was finally implemented last month.

"We want our people to have economic growth and development, we want them to have cultural development. If that change happens it can have an impact on the destiny of every citizen in this country."

The nuclear deal has partly ended Iran's isolation but it has been followed by warnings from Khamenei that the military must guard against economic and cultural "infiltration" by foreign actors who aim to damage the Islamic republic's revolutionary principles.

Although parliamentarians backed Rouhani on the nuclear deal they did so less out of a sense of support for the president than because Khamenei made it clear he wanted sanctions lifted.

Electioneering in Iran is heavily restricted.

Would-be lawmakers are not allowed to make speeches in the street, and at venues where they are permitted to address voters or supporters, placards, posters or use of outside loudspeakers are forbidden.

Only 15-by-20-centimetre (six-by-eight-inch) posters of their credentials or policies are allowed to be put up or distributed.

Although 290 seats -- 30 in Tehran alone -- are up for grabs in parliament many see the Assembly of Experts election as having much greater importance.

Its current task is to monitor Khamenei's work

But should the 76-year-old supreme leader, who underwent prostate surgery in 2014, die during the next assembly's eight-year term its bigger role would be in choosing his successor.

Assembly hopefuls were also cut drastically by vetting. Of the 800 who applied only 161, all men, were approved by the Guardian Council.

Rouhani is seeking re-election to the assembly and is allied in two 16-member lists for Tehran headed by himself and former two-term president Ayatollah Akbar Hashemi Rafsanjani.

The two have become increasingly close since the build-up to the presidential election in June 2013 that saw Rouhani voted into office on Rafsanjani's backing.