Iran on Friday dismissed as baseless a Canadian court ruling it had deliberately shot down a Ukrainian passenger jet, saying the court did not have the authority to issue a verdict.

The Superior Court of Justice of Ontario had on Thursday ruled that two missile strikes on the Ukraine International Airlines flight PS752 shortly after takeoff from Tehran on January 8, 2020 "were intentional" and "an act of terrorism".

All 176 people aboard were killed, including 55 Canadian nationals and 30 permanent residents, with the Islamic republic admitting three days later that its forces had shot down the Kiev-bound plane "by mistake".

Iran's foreign ministry spokesman Saeed Khatibzadeh said the verdict was "without any basis and objective evidence and reasons".

The court "has no authority to address this air incident" since it was outside its territory and jurisdiction, he said.

Khatibzadeh also accused the Canadian government of "exploiting the sorrows" of victims' families and alleged the court judge had followed "political orders".

The Canadian legal action seeking Can$1.5 billion (US$1.25 billion) was brought by four people who lost family members in the disaster.

At the time the jetliner was downed, Iran's air defences had been on high alert for a possible US counter-attack after the Islamic republic fired missiles at a military base in Iraq used by American forces.

Those missiles were fired in response to the killing of Iran's top general Qasem Soleimani in a US drone strike near Baghdad's international airport five days earlier.

In a final report in March, Iran's civil aviation organisation pointed to the missile strikes and the "alertness" of Iranian troops on the ground amid heightened tensions as among the causes of what Tehran had deemed as "human error".