0520 GMT April 19, 2019
A message on the embassy's website read: "The ability to provide consular services may occasionally be limited for short periods due to unsettled security conditions." It gave no more details.
The British Embassy in Cairo closed to the public on Sunday, also citing security concerns. A notice on its website on Monday said its services remained suspended.
CBC's Middle East correspondent Sasa Petricic said there have been security assessments in recent years that show the Canadian Embassy is particularly vulnerable in comparison to nearby embassies, including the British and American ones.
It is not set back from the street and is vulnerable on two sides, Petricic said.
Last month, a CBC News investigation showed that the Department of Foreign Affairs failed to spend almost half of the $129 million budgeted for “strengthening security at missions abroad” in 2013-14, leaving $69 million on the table.
Egypt is battling insurgents largely centered around the Sinai Peninsula, a strategic area near the border with Israel, Gaza and the Suez Canal.
Insurgent attacks have mostly targeted Egyptian police and soldiers, killing hundreds in the past year, but Egypt's most dangerous militant group, Sinai Province, said last week it was behind the killing of an American oil engineer in the western desert in August.
Smaller bombs also regularly explode in Cairo and the Nile Delta, usually causing limited injuries.
One security source told Reuters on Sunday it was not yet clear what threats had prompted the British Embassy to close its doors. But another source, who spoke on condition of anonymity, said a suspected militant who was recently detained by Egyptian authorities had confessed to plans to target foreign embassies.