Former Environment Minister Phil Hogan says people will be forced to pay more income tax if they do not pay water charges.
Ahead of today's water charges protests, the country's new European Commissioner said the Troika was "paying for the people who are marching".
Mr Hogan also dismissed criticisms of communications from Irish Water made by former junior minister Fergus O'Dowd. "The former minister was briefed on every issue, every part of the way in relation to the establishment of Irish Water," he said.
Mr Hogan, who oversaw the establishment of Irish Water, was speaking after he officially resigned as Fine Gael TD for Carlow-Kilkenny to take up the Agriculture portfolio in Brussels. He said the introduction of water charges in Ireland was "predicated by the unsavoury situation of the Troika" which forced the new tax on the country.
And the former minister said the Troika was paying the people who are now opposing the introduction of the measure.
"The people who are paying the piper - the EU, the IMF the ECB - who are paying for the people who are marching tomorrow, be it public servants or on welfare or on any particular services," he said on Newstalk.
"This is where we have been getting our money for the last number of years because we were broke, and unfortunately that has a huge impact on people's personal disposable income but also their lifestyle.
"We have to reform how we do business in this country or we will not learn from the past."
Mr Hogan said people have the choice of either paying more income tax or "paying as you use" for water.
"Water is not free," he said.
"It costs €1bn a year to supply water to all of the people of this country, so we either pay more on income tax to get the systems we have in place, which are not adequate at all for the future development of our country, or we pay as we use.
"It's never easy, people right across the European Union are paying as you use at the moment, people in Northern Ireland are paying for water through their service charges."
Asked about the countrywide demonstrations against water charges, Mr Hogan said no one will be able to get rid of the new charge. "People are entitled to protest, to make their voice known," he said.
Mr Hogan said the Troika was still looking over the shoulder of the Government despite exiting the bailout programme.
He said he would like to have been able to introduce water charges over a longer time frame but he was under pressure from the bailout partners to implement the measure.
Mr Hogan's dismissal of Mr O'Dowd came after the ex-junior minister described Irish Water as "an unmitigated disaster".
In an unprecedented attack from a government TD, Mr O'Dowd said Irish Water has "come across as arrogant and uncaring, demanding money and demanding PPS numbers".