Japan's benchmark Nikkei 225 opened 1.86 percent down, while the broader Topix index dropped 1.96 percent to 1,542.25.
The Topix opening fall took it 10 percent lower than an eight-year high hit on August 11. Both indices continued to slide after open, with the Nikkei dropping 2.05 percent in early trade and the Topic shedding 2.68 percent. Within 15 minutes of the market opening, the Nikkei had dropped to a near-five-month low.
Meanwhile, Korea's Kospi index dropped 0.5 percent to 1,866.2 points at the open.
And in Taiwan the financial regulator has unveiled a rule that discourages investors from short-selling local stocks, in the hope of propping up the local market.
The new rule from the Financial Supervisory Commission, unveiled on Sunday and to come into effect Monday, prevents investors from selling short a stock at a price lower than the previous session's closing price.
The regulator also said it would encourage local financial services companies to buy back their own shares and buy other Taiwanese stocks. The Taiwan market opens at 9am SIN.
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- Reuters contributed to this story.