TOKYO  Japanese companies are caught in a double bind, facing markets at home that are shrinking with the population as well as the global downturn. Nevertheless, companies must expand foreign sales aggressively  or face longer-term decline.

Exports from the world’s No. 2 economy fell an unprecedented 49 percent in February. But even as Japanese policy makers call for a renewed focus on domestic markets, companies are tying themselves more tightly to overseas markets and innovation.

“Japanese companies themselves just don’t see a future in the domestic market,” said Yasuo Yamamoto, senior economist at Mizuho Research Institute. “They’re looking for opportunities overseas instead of investing at home. That makes it almost impossible for Japan to reduce its export dependence.”

Prime Minister Taro Aso announced Tuesday that Japan would put together yet another economic package to stimulate demand, with steps to create jobs and further reduce taxes. Japan has already announced stimulus plans worth 12 trillion yen, or $122 billion, including 2 trillion yen in cash handouts.