OSAKA -- As the debate intensifies over allowing more foreign workers into Japan to make up for the coming labor shortage, human rights groups have recently stepped up efforts to push for a law against discrimination.

Yet despite calls from not only human rights nongovernmental organizations but also the United Nations for such a law, the central government says separate legislation is not needed because the Constitution provides sufficient protection against discrimination.

Japan's population is expected to decline from the current 127 million to about 100 million by 2050. The working population, defined as those between the ages of 15 and 64, is expected to shrink from the current 66 million to about 44 million by that year, according to government statistics.