While the severe weather watch for the Western Bay of Plenty had been lifted, MetService duty forecaster Hordur Thordarson said in Tauranga there would still be outbreaks of rain with 7-10mm overnight and another 5-8mm tomorrow.
He said the forecast for Boxing Day is for periods of rain and strong northerlies with possibly 20-30 km/h wind bursts increasing to 40-50km/h bursts at times on Thursday.
Friday is expected to also be rainy with light winds, and showers with little wind on Saturday and light winds and showers on Sunday.
MetService Chief Forecaster Peter Kreft said: "Evan will bring a large amount of tropical air over New Zealand, which means the potential for heavy rainfall in places with strong onshore winds.
"Christmas Day looks unsettled for many places," Mr Kreft said.
"By this time Evan will be over the Tasman Sea, maintaining the warm, humid northerly flow over much of the country. Rain over northern New Zealand will should have eased but not be completely cleared."