The decision came into effect October 21 and stipulates that Moroccans must provide proof of vaccination in order to enter their workplaces. In a statement, the government has said employers have "direct legal responsibility" to enforce the decision.

The pass is also required to access indoor services such as restaurants and banks as well as domestic and international travel.

The North African kingdom of 36 million people has Africa's highest vaccination rate, with more than 50 per cent of the population fully inoculated. Earlier this month, the government also started administering booster shots.

But the abrupt and unusually widespread vaccine requirements have also prompted opposition, and led to big crowds at vaccination centres as people rushed to get shots.

In the capital, Rabat, protesters gathered on Wednesday outside the parliament building and chanted slogans against the rule, arguing that it goes against fundamental human rights and civil liberties. Police formed a line to prevent the angry demonstrators from getting inside the legislature.

A few protesters clashed with police as they were pushed away down Mohammed V Avenue that leads to the parliament building.

Among protesters was Nabila Mounib, a member of parliament and the secretary general of the opposition Unified Socialist Party. She joined the protest after being barred from entering the parliament building for showing up without a vaccination pass.

Similar scenes unfolded in other Moroccan cities, with dozens of protesters taking to the streets in the country's most populous city, Casablanca, as well as tourist hotspots of Marrakech and Agadir.

They shouted "United against the pass!" as police pushed and swung batons at some of the demonstrators in an attempt to disperse them.

Australian Associated Press