A group of four countries, led by Canada, has asked Iran to submit to arbitration to settle a dispute over the downing of a Ukrainian plane.

After taking off from Tehran on January 8, 2020, Ukraine International Airlines flight PS752 was hit by two missiles. All 176 people on board were killed.

Three days later, Iran admitted to shooting down the plane by mistake.

The group, comprised of Canada, Sweden, Ukraine, and the United Kingdom, stated that it was taking "concrete action" against Iran.

The four countries have been seeking restitution on behalf of the victims' families, many of whom were citizens or residents of those countries.

They charge Iran's Islamic Revolutionary Guard Corps with "illegally and intentionally" launching two surface-to-air missiles at the jet.

Iran, for its part, stated that its air defences were on high alert at the time of the incident, following the firing of ballistic missiles at two Iraqi military bases hosting US forces amid heightened tensions with the US.

In a joint statement released on Wednesday, the four countries "requested that Iran submits to binding arbitration of the dispute related to the downing of Flight PS752" under a 1971 multilateral treaty on threats to civil aviation.

It said the group remained "committed to pursuing efforts to hold Iran accountable for the multiple breaches of its international legal obligations".

Eighty-five of the passengers on the flight were Canadian citizens and permanent residents.

"Those who lost loved ones in the downing of Flight 752 deserve justice," Canadian Foreign Minister Melanie Joly said in a tweet on Wednesday.

"This week, we took an important step forward in our international pursuit of justice, and we will continue to work together to hold Iran accountable for this tragedy."