OTTAWA (Reuters) - The Canadian wife and family of a former aide to ousted Egyptian president Mohamed Mursi are not being allowed to leave Cairo and Ottawa should intervene in their case, a family member said on Thursday.

Khaled al-Qazzaz, Mursi's former foreign affairs secretary, was freed in January after spending 18 months in detention. His wife Sarah Attia flew out to see him with their four children shortly afterwards but is now stuck there.

Attia's brother Ahmad said Egyptian authorities had twice stopped her at the airport as she tried to leave, had ordered the closure of her bank accounts and would not extend her visitor visa, leaving the family in legal limbo.

He also said al-Qazzaz needed surgery to treat injuries suffered in detention.

"The safety of my sister, her husband and, most importantly, her four children ... are seriously at risk. This is a Canadian family being persecuted in Egypt," he told a news conference.

"I am here today to call on Egyptians for their goodwill and to allow this family to return home ... and also to call on the Canadian government to help with this ordeal and to speak with the Egyptian government," he said.

Al-Qazzaz is a permanent resident of Canada but does not have Canadian citizenship. A spokeswoman for the Canadian foreign ministry said Ottawa was aware of the case.

"Canadian officials, including at the Embassy of Canada to Egypt, have been following recent developments closely and remain in regular contact with them," said Michelle Saucier, declining to give any more details.

Al-Qazzaz was arrested in July 2013 along with Mursi when the army removed the Muslim Brotherhood from power.

An official at the Egyptian embassy in Ottawa said the mission was trying to ascertain why the family was having difficulty leaving. He did not give more details.

In September, Egypt pardoned 100 prisoners, including Canadian journalist Mohamed Fahmy.

On his return to Canada, Fahmy said he felt "betrayed and abandoned" by the previous Conservative government, which he said should have done more to press his case.

The Conservatives lost an election in October to the Liberals.

(Reporting by David Ljunggren; Editing by James Dalgleish)