Transport Minister Marc Garneau says Canada wants Iran to explain why it hasn't yet handed over the black boxes from the Ukrainian jetliner that crashed near Tehran on Jan 8.

Garneau is speaking this morning by video link to the United Nations aviation organization's council and he says it has been 92 days since Iran told the council that it would give the flight data and cockpit voice recorders to Ukraine for analysis.

Iran had refused to hand over the recorders since the crash despite not having the technology to read the damaged machines itself but changed that stance on March 11.

Several days after the crash Iran admitted it shot down the aircraft, killing all 176 passengers and crew, saying an air-defence battery mistook the civilian jet for a hostile object in the middle of military tensions with the United States.

More than 50 of the passengers on the plane were Canadians and 138 of them were travelling to Canada, many of them returning to school and work after the December holiday.

Garneau says Canada expects Iran to fulfil its promise to hand the recorders over and says he would like Iran to give the International Civil Aviation Organization an update on why it hasn't done so yet.