An Egyptian court on Sunday sentenced 23 pro-democracy activists to three years in jail for organising illegal protests, the latest in several verdicts against political activists in recent months.

The defendants include activist Sanaa Seif, sister of prominent activist and blogger Alaa Abdel-Fattah, rights lawyer Yara Sallam, photojournalist Abdel-Rahman Mohamed of Al-Badil news website and photographer Rania El-Sheikh.

The convicted have also been fined LE10,000 (approximately $1,390) each and ordered to be placed under police surveillance for three years after serving jail time.

The defendants were arrested on 21 June for their role in a demonstration calling for the repeal of the protest law which bans demonstrations without police authorisation and punishes violators with imprisonment. 

Sana Seif, 20, also daughter of late well-known human rights advocate and lawyer Ahmed Seif El-Islam, has been on hunger strike for almost two months to protest the notorious law and the "unjust" detainment of thousands under the legislation, according to her sister Mona Seif.

Yara Allam, 28, is a lawyer with the Egyptian Initiative for Personal Rights, a leading human rights organisation, and a bilingual blogger who writes in English and Arabic. She won the North African Shield in 2013, a regional human rights prize. Eyewitnesses had said Sallam was not taking part in the protest, but was rounded up while walking nearby.

Among other accusations the defendants have been charged with are stirring chaos, illegal assembly, vandalism and possessing arms or fireworks.

Defense team lawyers Ragya Omran and Ali Abbas, have stated their intent to appeal.

"This is a politicised sentence. There isn't any evidence against the defendants," Abbas said after the verdict was announced, adding that the controversial protest law must be revoked.

Amnesty International had called for the release of these activists, saying the accusations against them are "baseless" and "farcical" and calling them prisoners of conscience who were arrested for defying a repressive law. 

A European Union delegation attended the Sunday hearing at a police academy courtroom south of Cairo.

Ahram Online reporter at the court said families and relatives of the defendants were in a state of shock over the sentence, with one family member fainting upon hearing the decision.

Alaa Abdel-Fattah, who was waiting for the ruling outside the courtroom, declined to comment on the verdict.

Abdel-Fattah, an icon of the 2011 uprising that toppled long-time autocrat Hosni Mubarak, has himself been in and out of prison since the popular revolt. He was sentenced in June to 15 years in jail for breaching the widely criticised protest law but was freed on bail on 15 September pending re-trial on the charges.

Abdel-Fattah and Sana Seif missed their father's death late in August while in prison but were granted permits to attend their burial and funeral, accompanied by police.

Dozens of detainees, activists and relatives of the defendants joined hunger strikes in recent weeks to demand the release of prisoners and call for an end to the protest law.

Since the ouster of former president Mohamed Morsi in July 2013, authorities have mounted a harsh clampdown campaign on Islamists in which thousands have been jailed.

The crackdown has also extended to several youth activists after the protest law was passed late last year, heightening fears of the future of political dissent in Egypt.

New York-based advocacy group Human Rights Watch condemned the sentencing on Sunday, saying in a statement that the Egyptian government  is" brazenly trampling on the rights of its citizens" and "will clearly go to any length to crush domestic opposition, whether secular or Islamist.”