New Zealand has experienced its warmest and wettest winter on record, scientists said Friday in the wake of widespread flooding last month on the South Island.

For the third year in a row, New Zealand recorded its warmest winter since temperature records began in 1909.

Researchers at the National Institute of Water and Atmospheric Research said the average temperature nationwide was 9.8 degrees Celsius (49.64 degrees Fahrenheit), which was 1.4 degrees Celsius warmer than average.

Institute scientist Nava Fedaeff said climate change "is strongly contributing to New Zealand's temperature trend".

For the first time, temperatures were more than 1.2 degrees Celsius higher than average in all three winter months.

Of New Zealand's 10 warmest winters on record, six have occurred since 2013.

This winter was also the wettest since rainfall records started in 1971.

Wild weather battered New Zealand last month, especially on the South Island where widespread flooding led to hundreds of homes being temporarily evacuated.

A phenomenon from the tropics known as an atmospheric river of moisture was to blame for the downpours, which saw states of emergency declared in Nelson, Tasman, the West Coast, and Marlborough.

Fedaeff said New Zealand's wettest winter is the culmination of numerous extreme rainfall events "which affected almost every part of the country at some point".