The Health Minister Leo Varadkar says the communications campaign about the necessity for water charges "has not yet been won".
His comments come ahead of a series of protests against the fee around the country this weekend.
Mr Varadkar says he believes the reasons behind the need for water charges must be communicated better.
And he has defended the use of PPS numbers by Irish Water:
The government is meanwhile facing a call to "stop the clock" on water charges. It comes ahead of what it is predicted will be a mass wave of more than 50 protests against the system over the coming weekend.
One of the groups involved, Right2Water, represents a number of unions, politicians and activists.
Spokesman Brendan Ogle says reports that the government will make some effort to calm the waters - like extending the flat rate period - will not wash with the public.
He told the Pat Kenny Show here on Newstalk earlier that people have seen through promises made by government.
Meanwhile the Communications Minister Alex White says the government has been "behind the curve" on Irish Water and "bit off too much too quickly".
Mr White was speaking amid mounting speculation over a potential extension of the flat rate, ahead of a national protest against the charge this weekend.
He also admits the coalition has been slow to reassure people over Irish Water's use of PPS numbers, which he says will allow people to claim tax relief.
The comments come as it is reported that the government has now instructed Irish Water to draw up an easy pay plan as an alternative to quarterly bills, as the coalition tries to calm public anger.
Council workers have said they will not install restrictors at homes which do not pay - meaning the utility company will be forced to bring in outside contractors.
Irish Water has said supply for homes which do not pay will be reduced to a trickle, to allow for drinking water, but will not be strong enough to run showers or washing machines.
What do you think? We asked these people in Dublin should you pay for water?
