Plans by the Government to scrap the current television licence fee in favour of a more wide-ranging one have come under fire.
The new charges will affect anyone with a laptop, tablet or smartphone at home, and will aim to crack down on the 12pc of householders who currently evade the €160 annual licence fee.
Solidarity TD Paul Murphy said if media charges were rolled out to every household in Ireland, the country would face water protest-style "backlash" demonstrations.
Mr Murphy was a high-profile figure during the water protests movement, which reached a climax in 2014 and eventually led to a government reversal of the tariffs.
The politician said he could see anger among the public if Communications Minister Richard Bruton's plan goes ahead.
"In reality this is a household charge," Mr Murphy told the Herald.
"There's a massive opposition to such a charge. If the Government try to go there, they'll face a backlash.
"People won't buy that it is something to do with broadcasting when everyone is paying the same charge.
"We could have substantial protests against this, like the water charges movement, depending on how the Government attempts to apply this charge."
People Before Profit TD Brid Smith warned that a future broadcasting tax "will hit people who may have no TV and do not access any such services, not to mention hitting all households regardless of income or ability to pay."
Meanwhile, An Post defended its record of TV licence collections after Mr Bruton announced plans to put collections out to public tender.
It said that last year it achieved TV licence sales revenue of €166m on behalf of the Department of Communications, with the sale of 1,038,986 TV licences.
"This represents a 1pc increase on the prior year and an additional €2m revenue for the department," an An Post spokesman said.
The State-owned postal provider released figures to the Herald showing that in 2017 it raised €1,027,596 in collections; in 2016, €1,019,169; in 2015, €1,018,444; in 2014, €1,018,370; in 2013, €1,013,606, and €1,003,860 in 2012.
"The television licence contract is an important part of An Post's business strategically, a key facet of our public service role and an essential income stream for our postmasters and the national post office network," the spokesman said.
"An Post has long argued that the contract needs to be longer term than the current annual renewal to allow for investment into databases and IT to facilitate more efficient collection.
"The 2018 evasion rate was 12.83pc, down from 14.1pc in the prior year.
"This 1.27pc improvement demonstrates An Post's commitment and focus in growing licence sales in a very challenging market rife with difficult conditions, many of which are outside the control of An Post."
The postal provider described licence fee collection as a "difficult and complex task".
"Achieving a compliance rate of 87pc under current conditions is a credit to An Post's licence collection team across the country," added the spokesman.
"An Post remains committed to delivering an effective and efficient TV licensing system and to providing great customer service throughout. We await the details of the planned tender which is due later this year."
Fianna Fail communications spokesman Timmy Dooley said that the plan "will do little to solve the current funding crisis in public service broadcasting".
National Union of Journalists (NUJ) general secretary Seamus Dooley said Mr Bruton's "private sector mentality" posed a threat to employment and to public service broadcasting.
He renewed the NUJ's call for a commission on the future of the media in Ireland.