MetService forecaster April Clark said a garden variety weak front was now moving up the West Coast that would stall mid-week bringing days of rain to the region. It would then move over the country in coming days mainly affecting western regions.
The lower half of the North Island from Waitomo south would be affected by showers but the rest of the island escaped any wet weather until closer to the weekend.
"It's only really from Taranaki south that will get any wet weather. Until Thursday it's not looking too bad for the North Island," said Clark.
Auckland, which was hosting the ASB Classic, could look forward to a mainly dry week with showers not threatening the city until Friday afternoon.
At the same time eastern regions would swelter in temperatures hovering around 30C. Masterton is due to hit 29C today.
Clark said the same record-setting summer temperatures scorching eastern Australia were unlikely to be felt in New Zealand with the heatwave generated and peculiar to the continent's own topography and climate conditions.
"At the moment just because they are getting a heat wave we won't necessarily get it," she said.
Today's temperatures: Auckland:Long fine spells. 24C Tauranga:Morning cloud, then fine. 27C Hamilton:Long fine spells. 25C Wellington:Mostly sunny. Cloud increasing at night. 23C Christchurch:Fine. 24C Dunedin:Light showers in morning then fine.19C