Counting was still going on in the capital Tehran, which returns 30 deputies to the 290-seat Majlis.
But results from two-thirds of the ballots counted showed a likely coalition of hardliners, conservatives and centrists on the cusp of crossing the 146-seat majority mark.
In contrast, reformists have managed to win less than 45 seats.
Some 58 seats will have to be contested in a second round, but with most reformists already eliminated before the polls, the second round of voting is certain to add to a crushing conservative majority.
Friday's voting was overshadowed by the mass blacklisting of reformists by the Guardians Council, a hardline political watchdog that screens candidates for public office and vets laws for their compliance with the constitution and Islamic law.
US and EU lambasted
Iran's foreign ministry on Tuesday angrily hit back at what it said were "unacceptable and interventionist comments" from the United States and European Union (EU) over the elections.
The foreign critics were "not informed of the realities and the complexities of developments underway in Iran", spokesman Hamid Reza Asefi told the state news agency IRNA.
Iranian spokesman Hamid Asefi said
critics are uninformed of realities
On Monday, the United States said the polls did not meet "international standards" and were "deeply flawed", given the blacklist. And EU foreign ministers called them a "setback for democracy".
Top regime figures here had called on Iranians to vote en masse to deal a blow to the United States, with which Iran has not had diplomatic relations since the 1979 Islamic revolution.
Ghulam-Ali Hadad-Adil, head of the conservative Builders of an Islamic Iran - a right-wing bloc poised to take all of Tehran's seats - told reporters the EU should avoid making "premature judgements".
Amid the international criticism, a political battle in Iran over the record low voter turnout continued to rage with the interior ministry hitting back at conservatives' allegations it was seeking to discredit their win.
Turnout for the poll was put at
The reformist-run ministry, responsible for organising the polls and overseeing the vote count, put turnout at 28% in Tehran and 50.57% nationwide - the lowest for a major election in the 25-year history of the Islamic republic.
This was contested by the Guardians Council, which along with the conservative press put turnout at a more respectable 60%.
The interior ministry responded in a statement by pointing to a "lack of information and negligence" and "propaganda" by its critics.
Rather than contesting the number of people who had voted, conservatives had questioned the number of eligible voters.
Turnout became a key issue in the polls, with many viewing participation as an indication of public support for the regime.
But the dispute is unlikely to be more than a temporary distraction from the result - a victory for conservatives, an end to Iran's often traumatic experiment with political and social reforms, and the isolation of reformist President Muhammad Khatami.
Conservatives also countered that compared to many Western democracies, a 50% turnout was perfectly respectable.