The people of Limerick are expected to be voting for their own mayor by May 2021.
The deadline was outlined by the Implementation Advisory Group, which met for the first time on the issue in Limerick today.
Limerick was the only city that voted in favour of electing its own mayor in a plebiscite in May.
The issue was also put to citizens in Cork and Waterford, but was rejected there.
It is a major reform of local government giving more powers to the mayor with a direct mandate from the people.
The group that will work out the details of implementing change met for the first time today with the aim of having an election in 2021.
The chair of the group is former foreign affairs diplomat Tim O'Connor, who was also consul general in New York for several years and secretary general to former President Mary McAleese.
He said the implementation group will carry out its work on the details that are needed to bring about the changes in local government over the next six months and report to Government by next June.
The group is made up of local councillors, members of the Limerick city and county executive, as well as academics and business people in Limerick.
It is expected that legislation will be enacted by next autumn, with the aim of having the election for the first directly elected mayor in the country by May or June of 2021.
Dr Diarmuid Scully, from the Centre of European Studies at the University of Limerick, warned that a change of government that may result from the general election next May should not halt or slow down the process.
The former mayor of Limerick is one of the members of the implementation group.
Minister of State at the Department of Housing Planning and Local Government John Paul Phelan, who met the group this morning, said there had been cross-party support for the idea of directly electing mayors, and that it would rebalance the deficit in local government.
He did not expect any delay in the process even if there was a change of government.
This was a national project and the experience in Limerick could be used as a template to have directly elected mayors across the country, the minister said.