The dollar ticked higher on Wednesday as renewed tensions in the Gulf and a potential energy shock boosted demand for safe-haven currency, Reuters reports. Oil prices edged up after separate reported attacks on shipping by the United States and Yemen's Iran-aligned Houthis, with Tehran saying the Strait of Hormuz would remain closed unless Washington accepts its conditions.

Markets are focused on U.S. inflation data due later Wednesday for signals on Federal Reserve policy. Economists expect inflation picked up last month after easing in June. Fed funds futures imply a 50 per cent chance the central bank will leave rates unchanged at its meeting ending September 16, according to the CME Group's FedWatch tool.

The U.S. dollar index, which measures the greenback's strength against a basket of six currencies, was up 0.05 per cent at 99.85. The yen weakened 0.05 per cent to 159.38 against the dollar despite joint intervention by U.S. and Japanese authorities, while the euro was down 0.05 per cent at $1.1536, Channel NewsAsia business reports.