Opposition parties have called a meeting on Wednesday to "condemn Colau's government in the face of its incompetence and inability to offer a response to the problems that are damaging Barcelona," the main opposition party PDeCAT tweeted.
The crisis kicked off last Wednesday when a US tourist was assaulted by street vendors, sparking criticism from an opposition which denounces an increase in insecurity in the seaside city, a major tourist magnet.
Colau, who is usually very active on social networks, did not respond.
But Albert Arias -- in charge of the city's tourism strategy -- did.
"Right, so a guy fights with another guy and suddenly the city is Gomorrah, the country is sinking, the newspapers heat up and in the end, hey presto, it's Colau's fault as she doesn't do a thing," he tweeted ironically on Sunday.
"Quite frankly you can go fuck yourselves."
He later apologised and took his account off Twitter.
The US tourist who was assaulted was briefly hospitalised for head injuries.
Opposition parties are also denouncing insecurity in districts like El Raval in the centre, home to so-called "narco-flats" where drugs are sold are rife.
On Saturday, men with knives and sticks were caught on camera fighting each other.
"She has failed as a mayor and as the one in charge of security. She must resign and allow for a change," said Santiago Alonso, spokesman for the centre-right party Ciudadanos.
Any condemnation of Colau will merely be symbolic as none of the parties has raised the possibility of a no-confidence vote to oust her just nine months ahead of municipal and regional elections in Spain.