The Irish government has slotxo committed €3m (£2.55m) to progress work on the cross-border Narrow Water Bridge project.
The proposed connection between Warrenpoint, County Down, and Omeath, County Louth, has faced a series of delays and shortfalls in funding.
Taoiseach (Irish prime minister) Micheál Martin said more money from the Shared Island Fund would be allocated once final costs are determined.
Contractors will soon be able to bid for the project.
The bridge would connect the A2 Newry to Warrenpoint dual carriageway in Northern Ireland with the R173 at Omeath in the Republic of Ireland, linking the Mourne Mountains and the Cooley peninsula.
It will also allow better access between the villages of Warrenpoint and Rostrevor in Northern Ireland and Carlingford in the Republic of Ireland. The area around Carlingford Lough is a major tourism destination in Ireland.
Construction is expected to begin in 2023.
It is understood the plans involve establishing a subgroup of the North-South Infrastructure Group, which will include Louth County and Newry, Mourne and Down District councils, to oversee the development and delivery of the project.