The New Zealand dollar fell against the US dollar, touching a three-week low, after Federal Reserve chair Janet Yellen said the central bank needs to push on with gradual rate hikes despite weak inflation.
The kiwi dropped to 72.04 US cents as at 8am in Wellington, and earlier touched 71.67 cents, from 72.45 cents late yesterday.
The trade-weighted index fell to 75.75 from 75.91.
In a speech to the US National Association of Business Economics, Yellen said there was a risk the labour market would become overheated without further increases in the fed funds rate and that "persistently easy policy can hurt financial stability".
Newly appointed Atlanta Federal Reserve Bank president Raphael Bostic also signalled a willingness to tighten monetary policy, saying there were more consistent signs of inflation.