New Zealand's annual inflation rate eased to 0.1 percent in the 12 months to March, the lowest in 15 years, official data showed on Monday.

The cost of living actually fell for the second consecutive quarter, off 0.3 percent in the January-March period largely due to declining petrol prices, Statistics New Zealand said.

"The fall in the March quarter CPI (inflation), which last happened in 2001, was caused by an 11 percent fall in petrol prices," SNZ prices manager Chris Pike said.

"Without petrol, the CPI rose 0.3 percent."

Pike said the 0.1 percent annual figure was the lowest rise in inflation since the September 1999 quarter.

The data is likely to see the Reserve Bank of New Zealand leave interest rates unchanged on 3.5 percent at its monetary policy meeting next week.

The central bank, which has an inflation target of 1.0-3.0 percent, has kept rates on hold since July last year.