The Australian and New Zealand dollars weakened for a third day as concern China’s economy is slowing sent a gauge of raw-material prices toward a 16-year low.

Currencies of economies tied to commodities have underperformed developed-market peers this year as their central banks cut interest rates to support growth, while the Federal Reserve prepares to tighten monetary policy. Economists predict an industry gauge Wednesday will show China’s manufacturing shrank for a seventh month.

Australia’s dollar fell 0.1 percent to 70.81 U.S. cents at 9:13 a.m. in Tokyo, extending its three-day decline to 1.5 percent. New Zealand’s currency slipped 0.1 percent to 62.87 U.S. cents.

The kiwi has tumbled 14 percent and the Aussie has slumped 7.4 percent this year, the worst performers of 10 developed-nation currencies tracked by Bloomberg Correlation-Weighted Indexes. The U.S. dollar rose 8.7 percent and the yen gained 8.3 percent.

Japan’s currency fell 0.1 percent to 120.26 per dollar Wednesday, after gaining 0.3 percent on Tuesday. Japan’s markets are closed until Thursday for public holidays.

Source: Bloomberg