Thousands of protesters demonstrated in several cities on February 20 demanding political reform and limits on the king's powers [EPA]

King Mohammed VI of Morocco has announced changes will be made to the kingdom's constitution aimed at improving democracy and the rule of law in the North African country.

"We have decided to undertake a comprehensive constitutional reform," King Mohammed said in a televised address on Wednesday, underlining his "firm commitment to giving a strong impetus to the dynamic and deep reforms... taking place".

The monarch announced the formation of a commission to work on the constitutional revisions, with proposals to be made to him by June.

A referendum would be held on the draft constitution, he said.

He also pledged that future parliamentary elections will be free and that the head of the winning party will form the new government.

The live broadcast was the first time the king has delivered an address to the nation since thousands of people demonstrated in several cities on February 20 demanding political reform and limits on his powers.

Six people were killed in unrest that erupted after the demonstrations, including five found burned to death in a bank set ablaze by people whom officials labelled vandals.

Another 128, including 115 members of the security forces, were wounded in the violence and 120 people were arrested, the interior ministry said.

Dozens of vehicles and buildings were also damaged or set alight.

There have been other peaceful rallies since then, including in the capital Rabat and the country's biggest city Casablanca, with young activists campaigning for greater democracy using the Facebook social network to call for
new demonstrations on March 20.