An agency set up to promote the long-running idea of a tunnel under the Strait of Gibraltar says work will begin in 2030, according to reports.
The society had previously conceived the Gibraltar link as a 42km rail tunnel connecting the Moroccan port of Tangier with the municipality of Tarifa, near Cádiz.
According to reports cited by La Razón, SECEGSA said coordination meetings would be held between Spanish and Moroccan experts.
The idea of a bridge or tunnel across the strait has been under discussion since 1979, and numerous studies have been carried out into its feasibility. Previous reports put the construction time at 15 years and the cost at $5bn, a figure that is around 20 years out of date.
A 2007 report predicted that the line would carry 9 million passengers in the first year, rising to 11 million after 10 years.
New interest in the scheme follows an improvement in relations between Spain and Morocco, intergovernmental discussions held in April last year and the availability of finance for the pipeline.
The World Bank, the European Investment Bank, the African Development Bank and many Arab donors have expressed an interest in funding it.