Two Canadians released from an Egyptian prison after being held without charges since mid-August have barred from flying out of the country, Cairo airport officials said.

John Greyson, a Toronto-based film-maker and York University professor, and Tarek Loubani, a physician from London, Ontario, had checked in for a flight to Frankfurt, Germany on Sunday, but were prevented from boarding the plane after their names appeared on a "stop-list" issued by prosecutors, the airport officials said.

The two Canadians retrieved their luggage and were free to leave the airport, the officials said, speaking on condition of anonymity because they were not authorized to brief reporters.

The pair had been released on Sunday morning after being held without charges since mid-August. They say they were observing an anti-government demonstration Aug 16 when Loubani heeded a call for a doctor and began treating wounded demonstrators while Greyson recorded the unrest on video.

'Red tape'

Greyson's sister, Cecilia, said Canadian consular officials were dealing with what she called "red tape" so they could begin their trip back to Canada. She said the family won't be fully relieved until the pair return home.

Earlier Sunday, she told Canadian TV station CP24 that she had spoken to her brother for the first time since his arrest and was relieved to find him healthy and happy.

Canadian Prime Minister Stephen Harper welcomed the news of their release, issuing a statement from the Malaysian capital of Kuala Lumpur where he's continuing a visit aimed at strengthening ties with that Southeast Asian nation.

"The government of Canada has obviously been pushing for that and welcomes this decision by the government of Egypt and we look forward to seeing these two Canadian citizens return home in the not too distant future."

Loubani and Greyson got caught up in the unrest surrounding the ouster of Islamist President Mohammed Morsi in a coup. They had been planning to travel to Palestinian-ruled Gaza, where Loubani was to teach emergency room medicine and Greyson was considering producing a documentary.

The men released a statement a week ago saying they were beaten and subjected to degrading treatment. Canada's foreign minister warned Egypt that the detention was a significant threat to relations between the two countries.