Winter is here: NIWA reveals what weather to expect

New Zealand is likely to see near-or-above-average temperatures this winter, but not without some cold snaps, the National Institute of Water and Atmospheric Research (NIWA) says.

A colder than average winter is "very unlikely" for New Zealand this year, meteorologist Chris Brandolino told The AM Show on Thursday.

"We're not talking the weather day-to-day forecast, we're giving the overarching theme."

As for rain, near or below normal levels are expected for the top of the North Island and east of the South Island over the next three months. The rest of the country is likely to experience near-normal rainfall.

A good ski season depends on many factors, and Mr Brandolino says it's likely the season could get off to a slow start in June due to a dry early winter, especially for South Island ski fields.

Overall, Kiwis can look forward to a fairly settled winter.

Weekend forecast: Heavy rain

The British and Irish Lions will get an early taste of New Zealand's winter climate as heavy rain, slips and flooding are forecast for Auckland, the Coromandel Peninsula and Northland on Friday.

A low pressure system over the Tasman is expected to move east and hit the north of the North Island on Friday morning.

In the 15 hours from 8am the day, up to 90mm of rain could fall in Northland and north of Orewa in Auckland.

People living in these areas are advised to look out for rapidly rising streams and rivers, and slips and surface flooding is possible.