Hourly services could be introduced on the Belfast to Dublin railway line, ministers said today.
Train operators are considering further development that would also involve new engines and the removal of speed restrictions.
The matter was discussed at today's transport meeting of the North/South Ministerial Council in Killadeas, Co Fermanagh.
Northern Ireland Regional Development minister Conor Murphy confirmed: "We want an increase in frequency of the service and also the time taken. It is a rolling programme over a number of years, and it will require significant investment from both administrations, north and south."
Officials are considering limited-stop services and how to deliver the changes. Mr Murphy has already earmarked sizeable funds for improving the road to Dublin but said public transport must not lose out.
Mr Murphy was meeting Minister for Transport Noel Dempsey, and there will be further ministerial talks in December 2007.