Taoiseach Enda Kenny has said he expects more people to pay their domestic water charges after it emerged Irish Water collected less than half the revenue due in the first three months of billing.

Mr Kenny said the charges were very fair and the Government had been quite clear that water would not be cut off and people would not be sent to jail for not paying.

Sinn Féin deputy leader Mary Lou McDonald said the Taoiseach would be “sorely disappointed’’ if he sincerely hoped more people would pay.

“You have comprehensively failed to win the support of the people for the introduction of this charge,’’ she added.

Fianna Fáil leader Micheal Martin said the Government was probably the first he had come across in history that had would actually lose money after introducing a tax.

Mr Martin said if you did not pay your bill, you would be rewarded with a €100 conservation grant. “It is quite extraordinary.’’

Earlier, Minister for Environment Alan Kelly said a payment rate of 46 per cent for all domestic water charge payments represents an “encouraging start to a long-term project”.

Mr Kelly said a “significant income stream has now been established and multiples of that funding can be converted into borrowing”.

About 675,000 households have paid the charge during the first three-month billing period. “Irish Water have formally written to my Department confirming these figures are in line with expectations and there will be no changes to their financial plans,” he said.

People Before Profit TD Richard Boyd Barrett said Irish Water was deluding itself and that the non-payment figures signalled a further escalation of popular rebellion against the charges.

“If the Government had any respect for democracy and the will of the people they would take this message for what it is, an overwhelming rejection of water charges by the citizens of this country.

“These figures show that the continuing and growing boycott of water charges along with further planned mass demonstrations in the run in to the general election can secure a victory in the campaign against water charges,” he said.

Minister for Transport Paschal Donohoe described the payment as slightly ahead of those for the Household Charge at the same stage.

"This level of compliance has been achieved before reminder letters went out to people and before any of the additional messaging Irish Water can do has had an effect," Mr Donohoe told RTÉ's Morning Ireland programme.

Irish Water has calculated it should take in €271 million in a full year of operation, meaning it should collect €66.8 million in its first quarterly billing cycle of January, February and March – with bills sent out from April onwards.

Minister for Health Leo Varadkar also defended the payment rate, saying he expects it to rise. “Irish Water is a long term project and as things stand just under half of people have paid without any reminders even issued at this stage so I’m confident that figure is only going to rise over the next months and years.”

Minister for Agriculture Simon Coveney said “I think it’s important to say that Irish Water are very happy with this start; 675,000 people have now paid their first water bill and the process is really only underway and reminders need to be sent out”.

The money collected for the first three months stands at €30.5 million, or 46 per cent.

The figures for the first quarter include homes in ghost estates and up to 5 per cent of people Irish Water does not have addresses for and haven’t sent bills to.

The figures do not include non-domestic bills, such as businesses, schools and hospitals, which are running at around 90 per cent payment of all money due. However, non-domestic charges were already being paid before the introduction of domestic water charges.

The number of households that have paid is 675,000 out of 1.5 million, or around 43 per cent.

Sources claimed the percentage figure for money collected is more important because it reflects the levels of payments made.

The difference in percentage between the money collected and households that have paid is because of different amounts of money charged per bill, sources said.

"Every bill is different," said one. It was also pointed out that the average time for someone to pay their water bill in the United Kingdom is three months.

The first cycles of bills also show 40 per cent of people paying through metered charges, rather than capped charges of €260 per two adult household and €160 per single adult households, beat the cap with lower water charges.

The bills from the second billing cycle of April, May and June are being sent out from this month. Reminders will also be sent from now on to houses which have not paid their bills.

Failure to make any payments over the first year of billing means a penalty sum of €30 for an one-person household and €60 for all other households will apply. Irish Water will also have the power to introduce attachment orders to deduct unpaid bills from wages and welfare.