Wales needs migrants if the country "is to maintain and grow its population" according to The Bevan Foundation.
The think tank analysed recent trends in population and population forecasts up to 2037. Researchers say they found declining birth rates in Wales, meaning the country is not naturally growing its population. Instead population growth has come from people moving here from the rest of the UK and overseas.
The Bevan Foundation claim that with zero migration, Wales' total population is expected to fall. They say modest levels of migration mean the population of working age will still shrink by as much as 9%. At the same time, the number of people aged 65 or over is predicted to increase.
Research Officer for The Bevan Foundation, Lucy Stone, says "Any fall in the number of people coming into Wales now will affect Wales' population growth in the future". She says a drop in population could put "strains" on areas of society.
Commenting on the findings, the think tank said it recognises that immigration can also raise issues about integration in Welsh society and culture. Researchers also said it would be exploring the impacts of immigration on the Welsh language in the future.