Foreign ministry spokesman Hamid Reza Asefi said complaints from the United States and the European Union that the polls were "flawed" amounted to "unacceptable and interventionist comments".
But Washington, meanwhile, stepped up its criticism.
"I join many in Iran and around the world in condemning the Iranian regime's efforts to stifle freedom of speech ... in the run up to the election," said President George Bush.
"Such measures undermine the rule of law and are clear attempts to deny the Iranian people's desire to freely choose their leaders."
With the vote count from Friday's elections looking set to drag on into Wednesday, results showed a likely coalition of hardliners, conservatives and centrists on the cusp of winning a majority from the first round.
"I join many in Iran and around the world in condemning the Iranian regime's efforts to stifle freedom of speech ... in the run up to the election. Such measures undermine the rule of law and are clear attempts to deny the Iranian people's desire to freely choose their leaders"
Counting was still going on in Tehran, which returns 30 deputies to the 290-seat Majlis.
But results from more than two-thirds of the ballots counted showed right-wingers set to win about 160 seats.
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 is certain to produce an even more solid conservative majority.
Friday's voting was overshadowed by the mass blacklisting of reformists by the Guardian Council, a hardline watchdog that screens candidates for public office and vets laws for their compliance with the constitution.
The US 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".
But the foreign ministry there said the critics were "not informed of the realities and the complexities of developments underway in Iran".
And Gholam-Ali Hadad-Adel, 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".
Top regime figures had called on Iranians to vote en masse to deal a blow to the US, with which Iran has not had diplomatic relations since 1979.
However, the Builders' party said on Tuesday Iran would continue cooperation with the UN's nuclear watchdog and approve tougher International Atomic Energy Agency (IAEA) inspections of its civil nuclear programme.
"We don't want to put the clock back on reforms, we just want to adjust the clock. We have certain complaints over things that have been done in the name of reforms and we will try to correct them"
Builders of an Islamic Iran chief
Hadad-Adel also pledged his party would not reverse the reforms implemented by the previous pro-reform parliament and President Muhammad Khatami, although it would seek some changes.
"We don't want to put the clock back on reforms, we just want to adjust the clock," he said.
"We have certain complaints over things that have been done in the name of reforms and we will try to correct them."
Amid the criticism, a political battle 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.
The ministry, responsible for organising the polls, put turnout at 28% in Tehran and 50.57% nationwide - the lowest for a major election in Iran's history.
This was contested by the Guardian Council, which put turnout at a more respectable 60%.