They said that investors in the region were keeping a close watch on the Shanghai market where share prices extended losses in morning trade as a keenly anticipated speech by Premier Wen Jiabao's provided few new leads.
Tokyo led the way lower with the benchmark Nikkei-225 index down 2.
34 percent in mid-afternoon trade, dropping below the 17,000 points level for the first time in almost two months.
Dealers said that exporter shares were hit by a stronger yen, which rose to the highest level for almost three months against the dollar, undercutting the overseas earnings of Japanese companies.
"A short-term bottom is not in sight right now as shares are still on course for a further decline," said Norihiro Fujito, chief analyst at Mitsubishi UFJ Securities, warning that the 16,000 points level was within range.
The recent slide in Shanghai was a major trigger for the falls in Tokyo, "but concerns about prospects for the US economy are also playing a key role in this downturn," he adde