Concerns over high numbers of spoiled votes have prompted an Oireachtas committee to call for modernised ballot papers and the use of plain English in referendum questions.

Sinn Féin TD Pádraig MacLochlainn, chairman of the public service oversight committee, said there was widespread voter confusion about the wording of the referendum proposing the abolition of the Seanad in October 2013.

A total of 14,355 spoiled votes were recorded in the referendum which the Government lost. The figure was described as a “matter that should cause great concern,” by Mr MacLochlainn.

“I am... at a loss to know why so many voters spoiled their vote but of concern has to be the fact that the ‘question’ was, for all intents and purposes, a double negative,” he said.

The committee’s report recommended that consideration be given to modernising how questions are posed and that the wording of referendum proposals be proofed in advance. “In this regard both the use of plain English and the phraseology of same is vitally important,” the report stated.

The committee also called for a permanent electoral commission to be established with a mandate to conduct research.

It was noted that while the layout of General, European and Local Election ballot papers have evolved to include a colour photograph of each candidate, the format of referendum ballot papers had remained largely unchanged since 1963.

Mr MacLochlainn said that was the year RTÉ television went on air. If the same pace of change applied to the national broadcaster, “then the Irish public would only have a one-channel national television service that broadcasts for only five to six hours per day, in black and white”.

He also provided figures for spoiled votes in last month’s European and Local Elections. A total of 45,424 votes were spoiled in the election to the European Parliament, while more than 19,400 were spoiled in the local authority poll.

A constituency by constituency breakdown for the European Elections found that 21,798 voters spoiled their votes in the South, while the figure was 17,258 in Midlands-North-West and 6,368 in Dublin.

The report said the proposed permanent electoral commission should research holding multiple referendums or a national election and referendum on the same day.

It should investigate the colour and layout of ballot papers, and research how information could be distributed to voters though the use of the internet and social media technologies.