The head of migration at the Organization for Economic Cooperation and Development said the legacy of the COVID-19 pandemic will be a "reorganization of the migration map" as the international flow of workers is brought to an abrupt halt.

It said this would have serious economic consequences, and would also put foreign-born workers who are already away from home in a position of disadvantage.

The Organization, also known as the OECD, is an intergovernmental economic grouping devoted to improving world trade.

It has warned that the impact of this year's ongoing events will be felt for some time to come.

Across the dozens of member countries, the Financial Times reports, immigrants and their children currently account for more than one in five people.

However, in the first half of 2020, the number of residency permits given out by those countries fell by more than half compared to a year earlier, principally because of restrictions caused by the novel coronavirus pandemic.

Not only are people who had been hoping to travel abroad for work now less able to, but also pandemic restrictions such as the shutting down of travel and border closures mean those who are already away from home have in many cases suffered more than native-born counterparts.

Factors such as their use of public transport for work, the often lower quality living conditions, and also the nature of the work they are involved in, increases their likelihood of infection and job loss.

They had "a disproportionate incidence of death even in countries with universal access to treatment for COVID-19", said Stefano Scarpetta, the OECD's chief of labor and employment.

The shutting down of services such as schools and language classes have made it harder for the children of migrants to assimilate culturally, and their fall in income also means less money is being sent back home to their families.

OECD Secretary-General Angel Gurria said there are three key employment sectors that highlight the full impact of the pandemic on migration.

One in four doctors and one in six nurses are migrants, the report revealed.

Across the job market in general, migrants have suffered unduly, with almost 60 percent of the initial wave of job losses affecting immigrant workers. Their lifestyles have increased their risk of infection, with immigrants being twice as likely to test positive for COVID-19 in Scandinavia.

"It is very clear that 2020 will be marked by a historic decline in migration," said OECD migration chief Jean-Christophe Dumont.

Ylva Johansson, the European Union Commissioner responsible for migration issues, said the issues raised highlighted the huge contribution made by migrants, and the importance of defending them in the future. "Talking about integration it should not be us and them," she said. "They were on the front-line during the pandemic and they will be an important part of recovering."

It is not just OECD member states that are affected. In Saudi Arabia, for example, the number of migrant worker permits given in the first half of last year was around 550,000. This year, that has crashed to just 55,000.