The first tenders for a 1,028km motorway between Abidjan and Lagos, the capitals of the Côte d’Ivoire and Nigeria, will be published in January, an official from the Ecowas group of West African states has said.

Ebere Izunobi is chairman of Ecowas’ Spatial Development Initiative, the body responsible for designing the project.

He said the highway was approved by a meeting of heads of state, and that experts from the countries the road will pass through – Nigeria, Ghana, Togo, Benin and Côte d’Ivoire – had convened to assess its physical, economic and social aspects.

The Abidjan-Lagos Corridor is expected to cost around $15.6bn to build. It will connect up urban centres such as Accra, Cotonou and Lomé.

“We are currently in the design phase, and by the end of this year, once the design is completed, along with the environmental assessment and engineering design, the project tender documents will be made available in the market,” Izunobi said, reports business website Nairametrics.

He said transport infrastructure was now a top Ecowas priority.

Ashoke Maliki, Ecowas’ head of roads and railways, said the corridor was a “crucial socio-economic link”.

In the future, the corridor will have a railway. This was approved in 2016 but a lack of funding has stymied progress and there is currently no completion date.