Air Canada is running into official resistance in trying to comply with animal-rights activists' demands that it stop transporting monkeys used in laboratory experiments.
The Toronto Star reports the Canadian Transportation Agency has refused to endorse the change without a hearing.
Air Canada came under international criticism a year ago after news that four dozen monkeys from breeding farms in China had been shipped to Quebec in cramped wooden crates.
Animal-welfare organizations called on the airline last summer to refuse to transport monkeys destined for lab experiments.
Air Canada reacted by filing an amended tariff with the Canadian Transportation Agency last November "that would enable it to discontinue transportation of non-human primates intended for research and/or experimental purposes," spokesman Peter Fitzpatrick told the Star via email.
"It was a decision taken both to align our policies with those of many other major international carriers and in response to widespread public concern."
But the agency notified Air Canada this week that it would hold a hearing on the request because it had received another complaint about the proposed change.
According to the British Union for the Abolition of Vivisection, Air Canada is among a dwindling number of airlines - including Air France and China Southern - that still transport monkeys.
Other major carriers, including British Airways United Airlines, Virgin Atlantic, Qantas, Delta and China Airlines, refuse primate shipments, the Star reported.
It's not the first time the agency has blocked Air Canada's attempts to get out of the monkey-shipment business. In 1998, it ruled the airline could not refuse a shipment of monkeys after the Barbados-based company sending them complained.
Opponents of the practice have a Facebook page devoted to the campaign.
"The law is clear," Rebecca Aldworth, executive director of of Humane Society International Canada said in the group's release last August. "Air Canada has every right, and a moral obligation, to stop shipping animals, including primates, to labs for use in harmful experiments."