Weather: 'Record-breaking heat' from Australia heading to New Zealand

"Record-breaking heat" in Australia is heading our way, driving off the cold in return of the summer weather.

It's already begun as high pressure expands over both the North and South islands. Some inland areas are forecast to reach 30degC in coming days as the heat builds.

"This hotter phase of weather arrives Sunday and Monday and will continue through next week," Weather Watch says.

"By Sunday afternoon, temperatures will be pushing back in to the mid- to late-20s in many places, and next week closer to 30 degrees inland through both islands."

This will only increase as "record-breaking heat" in Australia crosses the Tasman. Hobart hit 38degC on Saturday, its hottest day in March since 1940.

"Adelaide (41degC) and Melbourne (37degC) were also feeling the heat yesterday as a trough ahead of a front funnels heat from the interior towards the southeastern capital cities. This warmer weather will move in to New Zealand this coming week too," Weather Watch warns.

"Hottest weather will be inland, especially later in the week when sub-tropical northerlies spread over more areas."

But it's bad news for farmers, with no respite for Far North farms or the pockets of severe drought in the Tasman region.

"Unfortunately, not a lot of rain is in the forecast this week for the areas that need it," NIWA says.