Several hundred activists took part in a one-day hunger strike in Cairo on Sunday to protest the ruling military council's continued use of military courts to try civilians.

The protesters said the symbolic action was intended to show solidarity with hundreds of prisoners now facing trials before military courts, including many held after deadly clashes in Cairo's Abbassiya district earlier this month.

"We are not military people, any of us, none of us should be facing military trials," said Mohammed Mustafa, a rights activist with an Egyptian NGO.

"After the revolution, I shouldn't have to be here, calling for the rights of a civilian to have a civilian trial. We should have our rights," he said.

Organisers said hundreds of prisoners facing military trials were participating in an open-ended hunger strike, though they gave no exact numbers.

The activists gathered in front of Cairo Journalists' Syndicate building for a rally to publicise their action, which comes shortly before Egypt holds its first presidential poll since the 2011 uprising.

Among those in the crowd was Khaled Ali, a labour rights lawyer who is running for the presidency.

"I am not here for the elections. The message that I am sending is that this country won't change until the military council leaves," Ali said, adding that he was participating in the 24-hour fast.

As curious passers-by took camera phone pictures of the crowd, protesters held up posters featuring the names and faces of civilians facing military trial.

"Tantawi, tell us the truth, have you arrested our children?" they chanted, referring to Egypt's military ruler Field Marshal Hussein Tantawi.

Official figures on the number of civilians facing military trials are hard to come by, but activists claim thousands of people across the country are being prosecuted before such tribunals.

Human Rights Watch said in March that the ruling Supreme Council of the Armed Forces had referred 12,000 civilians to military courts since coming to power, including children.