The New Zealand dollar has cracked 75 US cents for the first time in almost a year.
The kiwi hit 75.5 US cents before easing back to about 75.2 US cents.
Analyst says Japan's attempts to revive its economy by lowering interest rates, and speculation that the US Federal Reserve is considering pumping more money into the economy, has bolstered currencies like the kiwi and Australian dollar.
Slowing global economic growth and a weak US dollar have sparked talk of an international currency war as countries scramble to protect their economies.
For example, Brazil has doubled a tax on foreign investors buying domestic bonds to 4% to curb a strong real, boosted by high domestic interest rates and a commodity boom.
By 12.24pm on Thursday, the New Zealand dollar was trading at 75.17 US cents, 76.96 Australian cents, 47.36 pence, 62.34 yen and 0.5398 euro. The Trade Weighted Index was at 67.03.