Police said the network was headed by Abdelkader Belliraj, a Moroccan who lived in Belgium.
"The prime minister decreed the dismantling of al Badil al Hadari within the framework of the break-up of the Belliraj terrorist network and in the light of the proven links between this network and the creation of this party," the statement said.
The interior ministry said police discovered at least 34 weapons, including two assault rifles, when they raided homes and offices of the suspects.
Moroccan authorities have arrested more than 3,000 people since suicide bombings in Casablanca in 2003 killed 45 people.
Morocco considered banning the religious based Justice and Development Party (PJD) after the bombings but it survived the crisis.
The largest opposition movement, Al Adl Wal Ihssane (Justice and Charity), is tolerated by King Mohammed's government but banned from mainstream politics because of its open hostility to the monarchy.