Though the country has invested more in education and skills in recent decades, many adults are falling behind, the Paris-based organisation said in a report.

It explained that with a population aging rapidly and a growing skills divide between generations, Portugal needs to strengthen its adult-learning system.

Andreas Schleicher, OECD director for education and skills, said: “Raising skills is critical to Portugal’s long-term economic success and social well-being.

“Creating a more sustainable and responsive adult-learning system will help equip citizens of all ages with the skills they need to seize the opportunities of a rapidly changing labour time.”

The report also called for improved governance and financing mechanisms, such as establishing a “skills financing pact” between the government and social partners to enhance the sustainability of funding for adult learning.

Though the current adult-learning policies “show great promise”, more needs to be done to improve accessibility and flexibility of the system, the report said.

It added that the country should provide better information on the financial returns of improved skills for learners, employers and society.

The report, Skills Strategy Implementation Guidance for Portugal, was launched in Lisbon this week.