The resolution, which was put forward by Canada, was adopted by the third committee of the UN General Assembly last week by a vote of 79 to 32, with 64 abstentions.
The legislation primarily relates to human rights abuses committed during demonstrations that erupted across Iran over economic hardships last year.
It notes Iran has made some progress to prevent human rights abuses and welcomes continued efforts by the Islamic Republic's authorities.
However, the resolution also strongly condemns the use of the death penalty against minors and for drug-related crimes.
It goes on to urge Iran to address the "poor conditions of its prisons", Al Jazeera quoted the resolution as reading, and calls for the release of prisoners arrested during last year's protests.
The resolution further calls on Iranian authorities to cease "widespread and systematic use of arbitrary arrests and detention" and ensure prisoners are treated humanely, according to international norms and regulations.
Iranian authorities have slammed the resolution, saying it has no "legal credibility" because its sponsors have their own history of human rights abuses, Al Jazeera reported.
Earlier this week, the Iranian foreign ministry summoned the Canadian representative in Tehran in retaliation.
Iran complained to the Italian ambassador, who represents the North American state in the absence of formal diplomatic ties between the two nations, that Canada had become a shelter for Iranian criminals, who it refuses to extradite.
Several Iranians who are wanted for alleged financial and economic crimes have fled to Canada, which refuses to extradite them.
A number of Middle Eastern states also rejected the legislation.
Iraq, Lebanon, Oman and Syria all voted against the resolution. As did Azerbaijan, Armenia, Afghanistan, Pakistan and the rest of Central Asia, bar Tajikistan, which abstained.
Shame on the Lebanese government.#Lebanon among the countries who voted "No" to U.N. General Assembly condemnation of #Iran's human rights abuses.
Human rights abuses in #Iran are documented & spread worldwide. But of course, #Lebanon chooses to side with the Iranian regime. pic.twitter.com/vhf1ePGrxm
— Luna Safwan – لونا صفوان (@LunaSafwan) November 19, 2020
Meanwhile, earlier this week, Human Rights Watch (HRW) condemned Iranian human rights abuses, claiming authorities have failed to provide "any real measure of accountability" for the violent crackdown on protests last year.
According to Amnesty International, at least 304 people were killed and authorities continue to sentence dissenters who were arrested during the protests to imprisonment and flogging.
Iran researcher for the human rights watchdog said: "One year after the November crackdown, Iranian authorities have avoided any measure of accountability and continue to harass the families of those killed during the protests."
"Families of hundreds of victims, most of them from the more vulnerable segments of Iranian society, deserve to see those responsible for the serious rights violations held accountable."
It went on to call on the UN to establish an inquiry into the abuses and violations perpetrated by the Iranian authorities during the early days of the protests.