The Government is bracing itself for the biggest display of public opposition to one of its policies as tens of thousands of people prepare to take part in anti-water charge protests across the country today.

As nervousness grew across Government last night about the potential scale of the marches, Tánaiste Joan Burton conceded a flat payment – likely to be at the assessed water charge rate – will be introduced for a “period”, as well as measures to ensure the charges are “modest and appropriate”.

"Let me tell people, the level of charges will be modest, but it will be sufficient for us to secure investment in water infrastructure," Ms Burton told RTÉ. "I think we will have the [flat rate] for a period of time, which is what makes sense, and then people who have meters can see what kind of usage they have. If their usage is below the charge, they will get a refund, so we want to build into this an incentive to use water more carefully."

Ministers are still working on a revised water-charges package, which will include the €100 household benefits package and water tax relief announced in the budget, with the tax relief possibly increasing to as much as €100 for every household.

Balance sheet

The tax relief measures are understood to be a way to give money back to homeowners while staying within the rules that allow the Government keep Irish Water off balance sheet. It means money still goes to Irish Water – so they can meet the rules of collecting a certain proportion from the public and businesses – but the State then gives people money back via tax relief and household benefit packages.

Many within Fine Gael have privately complained that Labour Party Minister for the Environment Alan Kelly has not defended his position better publicly. There was also criticism of how the issue has been handled by those at the top of Government, such as the Economic Management Council (EMC), but others maintained most of the responsibility lay with Irish Water and the Department of the Environment. Some complained about how Phil Hogan handled the issue when he was a minister.

Compliance

“There is a sense it will all be okay in the end,” one Cabinet Minister said. “There are some who think Alan Kelly should be out there defending his policy and decisions.”

Sources said there has been some consideration of increased compliance measures, with suggestions of involving the Revenue Commissioners, but this is seen as unlikely since water will be paid for through charges, rather than by a tax. One source said there is an acknowledgment water supports should not be given to those who are not paying their bills.

Labour backbencher Dominic Hannigan of Meath East last night said he will table a parliamentary party motion calling for a referendum to enshrine public ownership of Irish Water in the Constitution.

However, the prospect was dismissed by senior Government figures. "If we have a referendum on this, do we have one on the ESB, on Coillte? Where do we stop?" a source said.

Ms Burton said the additional package would not be unveiled for a “couple of weeks”.

A Government spokesman said to rush any decisions would be “bad practice”.