Reserve Bank of New Zealand recently increased their interest rates while Australia is affected by a slew of bad economic numbers from China. Yesterday's China's Industrial Production came out lower than expected. AUD will continue to be affected by China, its biggest export market for its mining output and thus, will likely continue to be pressured until China decides to inject more liquidity into its own money market (which has been strained recently).
Kiwi, on the other hand, is not so dependent on China. It raised its OCR recently to curb inflation.
http://rbnz.govt.nz/news/2014/5655497.html