Anxiety about a US economic slowdown are continuing to hit global markets

Asian markets have taken a massive tumble in the past 24 hours -- with Japan's Nikkei and the Taiwan Stock Exchange reporting their biggest one-day drops since 1987.

US and European markets have also followed New Zealand, Australian and Asian markets, down overnight.

Westpac Chief Economist Kelly Eckhold says these global sell-offs are reminiscent of the start of the Global Financial Crisis

He says there's a feeling that investors are starting to get "freaked out".