The law, introducing hefty fines for protesting without prior permission, is expected to be approved Thursday.
A number of Greenpeace activists gathered in front of the Spanish parliament, wearing gags and carrying placards stating "No to gag laws."
Decimos alto y claro NO a la Ley Mordaza http://t.co/wRo22XydIw #26MStopMordazas pic.twitter.com/KOxP4r482e
— Greenpeace España (@greenpeace_esp) 26 Март 2015
"The Partido Popular [one of Spain's major political parties] and Minister Fernandez [Interior Minister of Spain] have been deaf to the unanimous social and political rejection to the serious impacts on certain fundamental rights which the reforms to the Criminal Code and the Public Safety Law will have," Greenpeace said in a statement.
The law has sparked numerous nationwide protests all over Spain, with rights groups stating it is an attempt to silence the voices of the opposition.