"Southern Ocean storms are different to tropical cyclones, they cover a much greater distance and that spreads the energy much further, meaning many regions can have unsettled weather but it may not be severe enough to cause serious issues".
He said severe weather looks patchy but possible in both islands for a time.
It's too early to work out severe weather risks for New Zealand but some places - including majority of the South Island, Cook Strait and Auckland - could be in for severe gales, Duncan said.
He said by Monday and Tuesday we would be able to get much clearer picture of the severe weather warnings.
Heavy snow was looking likely in the South Island ranges and mountains for a time and heavy rain was forecast for the West Coast.
"Squally showers are likely along the western coastline of both islands."
But it's not all bad.
WeatherWatch forecasters say the angle of the winds and the fact that the centre of this storm should be well south of New Zealand, halfway between Antarctica and Southland, means not all have bad weather.
"The mountains and ranges will make for mainly dry and sunny skies in eastern areas of both islands, but windy at times."
A WeatherWatch forecaster said usually a big low at Easter would ruin outdoor events, impact travel plans and mean extra warnings for campers and trampers.
"However, with New Zealand at Covid-19 alert level 4 many of us are at home and a bit of windy, wet weather for a few days may not be too problematic."
