Taoiseach Enda Kenny and Fianna Fáil leader Micheál Martin have rejected claims that Fianna Fáil had approved the appointment of former senator Joe O’Toole as chairman of the expert commission on water services.

When Sinn Féin leader Gerry Adams said in the Dáil “I am reliably informed” that Fianna Fail had approved the appointment, Mr Martin immediately intervened to say that was not the case.

Mr Kenny also shook his head a number of times to indicate Fianna Fáil had not been consulted.

Earlier he defended Mr O’Toole’s appointment to the commission. He said he had done a great deal of work over the years as a public servant and senator.

“He has said he wants to be an impartial chairman”, Mr Kenny added.

People Before Profit TD Bríd Smith said she welcomed comments by Mr O’Toole about water services and charges because it exposed the commission’s approach.

Calls have been made for Mr O’Toole’s resignation from the commission after he made comments in media interviews that he personally believed that people should pay for water services.

Ms Smith told the Dáil that Mr O’Toole had declared that central taxation was insufficient to pay for water services, “that Revenue should be used to collect” the charge and while there would be “sweeteners” for those on social welfare and in poverty, “we have to find enough sugar to make the medicine go down”.

She said the outcome of the commission would be predictable. “There will be a form of company that will allow privatisation by the backdoor.”

The Dublin South Central TD asked Taoiseach Enda Kenny how the members of the commission were chosen and said there were no representatives of the State’s “largest social movement” against water charges or representatives of the trade union movement on the commission.

And she announced there would be a major demonstration in Dublin against charges in September.

Mr Kenny told her “thank you for the notification” about the protest.

He reminded Ms Smith that “this is one of the most important developments in the State for years and years because of neglect” of water services.

Mr Kenny told her “the city where you live has been on a knife edge” over lack of capacity for the population of Dublin.

“And that won’t improve without the advance of Irish Water” and its capacity to invest and supply clean water.

He said Irish Water had invested over €400 million since 2015 which was represented increase of 37 per cent”. He said that since 2014 Irish Water had built 20 new plants and upgraded 49 water treatment plants.

He said the trade unions and others would have an opportunity to have their say but “ the issue here was to have an expert advisory group”.

Ms Smith retorted that “I don’t know if you’re doing a Mary Poppins on this but you’re not answering my question”.

She said the members of the commission “are not impartial and in fact they are partial towards “a little bit of privatisation and a lot of charges”.

She said Mr O’Toole was partial and had “made up his mind” and the commission “is loaded with academics and people from outside the jurisdiction”.

She said people had applied to the commission who had expertise in the area but had not been given an explanation as to why they were not acceptable.

Mr Kenny said the people chosen had a particularly ability, experience and expertise in the area.

He said everybody had a view and everyone would have a say.

The Taoiseach added that “we can’t continue beyond 2016 with 60 or 80 plans woefully inadequate” and sewage going into rivers and lakes.

He said the Minister wanted to deal with this in a professional and efficient manner.

“You’ve a very different view of how Irish Water should be funded and the process will allow for all of these matters to be invested,” Mr Kenny told Ms Smith.