The Green Party has urged the government to go back to the drawing board on proposals for directly-elected mayors in Cork and Waterford and engage people through a Citizens Assembly process.
The party's spokesperson on political reform, Cllr Oliver Moran, said the narrowness of the defeat highlighted the deep demand for local government reform.
"If the Government are serious about reform of local government then the narrow rejection of this proposal needs to be taken as a mandate to go back to the drawing board and deliver something better," he said.
"Limerick will now have a directly elected mayor. I don't want Cork to be left behind but clearly the opposition to this proposal cannot be dismissed.
"The citizens' assemblies on same-sex marriage, on the Eighth Amendment, and on climate change have shown they clearly work in both capturing the public mood and making well thought-through proposals."
His call came as the war of words over the handling of the mayoral campaign in Cork intensified.
John Paul Phelan, the Minister of State with responsibility for local government reform, accused Fianna Fáil leader Micheál Martin of chickening out of the campaign in his home city.
He said while much of the focus was on the possible terms and conditions of the role, the narrow margin of defeat in both cities was proof that “outright political opposition” to the proposal was a major factor.
“The most glaringly obvious thing in Cork, which was completely the opposite in Limerick, where Fianna Fáil and the Collins faction in particular got involved in the campaign and supported it, Micheál Martin, who has been a supporter of directly elected mayors for many years, didn’t make a single statement of support for it,” the junior minister said.
“And in fact, his close councillors in Cork City Council virtually unanimously opposed it - he decided to essentially chicken out in favour of supporting his councillors as opposed to Cork city.”
Speaking to Morning Ireland, Mr Phelan also defended the government’s plebiscite campaign and the holding of the vote at the same time as the local and European elections which, he said, helped to guarantee voter turnout.
Meanwhile, voters in Dublin will get an opportunity to discuss the proposal for a directly elected mayor through the Citizens Assembly process, which the Minister said should be established this side of summer.
He said he expects it to be a relatively short process which should conclude over two or three weekends, with the vote likely to take place alongside one of the referendums due to take place next year.
And amid concerns about the high level of spoiled votes in the various elections this year, the Minister confirmed that an electoral commission will be established later this year to address issues like that.
He also suggested that it may be time to consider the introduction of certain minimum requirements to limit the number of candidates who can declare for European elections, which he said should have a slightly higher threshold for candidacy than is the case today, especially in constituencies with over a dozen counties.
Among the possible requirements would be the need for potential candidates to secure the nomination of 250-registered voters before being allowed to add their name to the ballot paper.