No, it's not because of Godzilla:
Commenting on a slumping birthrate which means Japan's population of 127 million could start shrinking in 2007, he told a news conference: "If we go on this way, the Japanese race will become extinct."
So, what is the minister implying?
According to a United Nations report in 2000, Japan is greying so quickly that it will need to import around 600,000 workers annually until 2050 to keep its working population stable. By then, if Japan follows the U.N.'s suggestion, nearly one-third of the population would be of foreign descent
Let's break this down. What's really happening here is that the government is trying to shift the blame for its inept handling of social security and pension funds. There's no reason that Japan needs to continue with the same size population unless the country's government has not taken the proper precautions for an aging population.
Here's my suggestion: implement Logan's Run in Japan, but move the age from 25 to 60. Problem sovled.