Reformists are hoping to pick up some seats in the key constituency of Tehran
Iranians have voted in run-off elections that are expected to confirm the dominance of conservatives in the country's 290-seat parliament.
Eighty-two seats in which no candidate managed to win 25% of the vote in last month's first round were contested in the second, including 11 in Tehran.
Conservative candidates won around 70% of the seats in the initial vote.
But correspondents say many are highly critical of President Mahmoud Ahmadinejad's economic policies.
If the conservatives continue to cause problems for Mr Ahmadinejad in the new parliament, this will strengthen Iran's Supreme Leader, Ayatollah Khamenei, they add.
There is no word so far on turnout. Results are expected at the weekend.
In the run up to the second round, Mr Ahmadinejad has been involved in several acrimonious exchanges with other Iranian officials.
And there has also been criticism from both reformists and conservatives about his latest cabinet reshuffle.
Eighth parliamentary election since 1979 revolution
43 million eligible voters
290 seats from 30 provinces, 82 contested in second round
About 40% of those who applied to stand were disqualified by the Guardian Council
On Wednesday, Iran's outgoing finance minister Davoud Danesh-Jafari added his voice to mounting criticism of the president's economic policies, saying Mr Ahmadinejad's government lacked experience and had no solid plans.
He accused Mr Ahmadinejad of giving priority to "peripheral issues" while allowing inflation to reach 18%.
Mr Ahmadinejad, who is expected to run for a second term as president next year, has come under fire for pumping excessive liquidity into the economy, which has been blamed for the rising inflation.
The BBC's Pam O'Toole in Tehran says Friday's polling is likely to determine just how easy a ride Mr Ahmadinejad will be given by the next parliament in the run up to the presidential elections.
Iran's reformists are trying to present a more united front in the second round of polling, our correspondent says.
But the size of the conservative victory in the first round, and the fact that many reformist candidates had been disqualified by the non-elected Guardian Council, means they appear resigned to trying to win a powerful minority in parliament.
Reformists will be hoping to pick up some seats in the key constituency of Tehran, where all of the 19 seats decided in the first round went to conservatives, but another 11 are up for grabs in this second round.