Thousands of leaflets will be distributed as part of a consultation process to homes and businesses along the four potential Luas routes for the new link connecting the Green and Red lines.
The public are being invited by the Rail Procurement Agency (RPA) to add their voices to the debate about which of the four routes would best serve their needs.
All four of the routes run from St Stephen's Green to O'Connell Street through Dublin's city centre.
Suggested routes from the Green include lines along Dawson Street and Nassau Street, a line serving Merrion Square and Pearse Street and a route running along South King Street and South Great George's Street to Dame Street.
Full details of the different proposals will be contained in the leaflets, which will be delivered shortly, the RPA said.
Minister for Transport Martin Cullen said the linking of the Red and Green lines will increase the numbers of people using the service by 25 per cent. He said this translates to around 5.5 million extra passengers per year.
"It will be an important segment in the overall public integrated transport system announced in Transport 21," he added.
Mr Cullen said he hoped to secure railway orders by next year with the new line being built and operating by 2008.