Morocco's main human rights group says the arrests of pro-democracy activists have increased since a new constitution was passed during the 2011 Arab Spring.

Mohammed Sadkou, a member of the Moroccan Association for Human Rights, said at Monday's news conference the activists are being charged with criminal offences like drug possession to mask their activism.

On Sunday, activists attempted to hold marches in several major cities, including Rabat, to call attention to their jailed comrades. Police violently dispersed the protests in each case.

Morocco was swept by pro-democracy protests in 2011, but the North African country managed to avoid wider instability by holding early elections and amending the constitution to give greater power to elected officials.

There are still about 70 activists in prison, according to rights groups.