Yesterday local MSP Michael Russell, who is also the Education Secretary, reacted furiously to news of the covert operations and demanded a full independent inquiry.
Jo Smith, the communications manager with Argyll and Bute Council, revealed the tactic at a conference on how the public sector could make more use of sites such as Facebook.
She told fellow communications professionals the tactic had been used to join Facebook groups to find out what critics of the council were saying.
In a letter to the council's chief executive Sally Loudon, Mr Russell said: "I cannot remember being as angry. The thought that my constituents have been 'spied on' by a senior member of your staff is truly outrageous. And when I consider the likelihood that I was one of these people, then words almost fail me."
He called for disciplinary action if Ms Smith's tactics were confirmed and said a council internal inquiry would be in-sufficient. "There are significant issues under the data protection and standards legislation that will require consideration. There will need to be a full and open account given of all these 'spying' activities and information produced as to where the 'product' of this spying ended up. Who saw it or was told of it? Did senior officials and administration councillors have access to it?"
Mr Russell said there were serious concerns about the running of Argyll and Bute Council, and alleged that staff from within the administration had used fake identities to target opponents of the regime with "aggressive" comments on other websites.
He added: "There is something wrong in this administration that needs to be looked at closely. A council is supposed to serve the local community. There appears to be some sort of dirty tricks campaign, including members of that team within the council commenting on members of the council not in the administration in very aggressive fashion."
After Ms Smith's presentation in Glasgow, one communications professional said: "You may not like what taxpayers are saying about you online, but you can't pretend to be one of them in order to find out what they are saying. Other professional communicators in the room were very uncomfortable about it."
The council is run by a coalition of the 13-strong Alliance of Independent councillors plus six LibDems and two Tories.
Speaking to The Herald prior to her suspension, Ms Smith claimed her comments about "spy accounts" had been taken out of context and it had not been carried out on Argyll and Bute council's time. "It was about trying to create a separate account different from your normal one that you have holiday photographs on. 'Spy account' was shorthand for it being another identity, to take you into a place that you wouldn't be comfortable using your main account. I'm sure people do this all the time," she said.
Ms Smith refused to discuss what groups she had joined, adding: "My online activity in my private life is private. You separate the professional from the personal and keep those two things separate. That is why many people post and say 'this isn't my employers' opinion'. There are no rules here."
Last night the Argyll First group of independent councillors backed Mr Russell's call for an external inquiry. They said: "If it is true that council officers and administration councillors are spying on constituents and opposition councillors, heads must roll. Argyll First fully supports the calls."
A spokeswoman for Argyll and Bute Council said: "The council does not, nor ever would, condone the covert use of social media. A full investigation is underway and a member of staff has been suspended."