In a statement, the president said the state of emergency would "free the country's roads" and "restore" normalcy.
Under law, Bolivia's Congress must approve or reject the measure within 72 hours of the declaration.
The blockades, led by miners, farmers and indigenous groups, are part of protests which started at the end of April.
Several people have died and hundreds have been arrested during the unrest.
Protest groups are calling for fuel subsidies to be reinstated and a rollback of austerity measures, as well as demanding Paz's resignation.
