Japan needs about four times more foreign workers by 2040 to achieve the growth path the government has outlined in its economic forecast, a group of Tokyo-based public think tanks said on Thursday.

The findings highlight a growing Japanese reliance on migrant labor to make up for a shrinking population while its ability to attract overseas talent has been thrown into question by strict COVID-19 border controls that have shut out students and workers.

Japan must boost the number of foreign workers to 6.74 million by 2040 to sustain average annual economic growth of 1.24%, based on a bullish "high-growth" scenario the government has set out in its long-term projection, the think tanks, including a research arm of the Japan International Cooperation Agency (JICA) affiliated with the Foreign Ministry, said in a report.