Auckland and Waikato farmers fear this latest rain deluge could undo the cleanup from last month's Tasman Tempest.

Auckland and Waikato farmers have a short, sharp message to the weather gods: No more rain please, we have had enough.

The upper half of the North Island experienced widespread rain over the past 24 hours with more forecasted as Metservice forecasts a thunderstorm watch for northern New Zealand, from Northland to Taranaki.

"I don't think you'll find a person in Auckland who will say we haven't had enough rain," South Auckland farmer Robert Cashmore said.

SUPPLIED A day earlier, the tail end of Cyclone Debbie drenched North Waikato.

Many farmers had only just finished cleaning up their farms following the previous storm in March, he said.

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"No one's had a chance to get around all of their farms to see if there's been any slips or if anything from the last [rain] event has moved any further."

The waterway that runs through his farm was high, but had yet to breach its banks like it did last month, when another severe storm struck.

As of lunchtime on April 5, Cashmore's rain gauge had collected 600mm over the four weeks since the last deluge.

"Our annual rainfall is 1000mm, so we have had over half of that in a month.

"We're pushing 160mm now, it was 150mm at lunchtime. It's not big rain, it's just that everything's a bit wet and I think it's going to be more of an issue of slips re-moving, especially the ones that people have tidied up with diggers already."

He was concerned this latest storm would undo the clean up farmers had undertaken over the past month, including access tracks and fencing.

"It has possibly moved some of those slips back onto those tracks."

That could make it difficult to access livestock shifted to higher paddocks once the storm passed.

Taupiri farmer Steven Stark said while there were some slips that had occurred on some of the steeper country, and there was flooding around the district, he had not heard of any farmers in serious trouble.

"It's still quite warm luckily. It's not as if it's the middle of winter and pouring down with rain.

"If it rains tonight it might be a different story. Everything's at the point where the rain came and we got away with it. If we get a lot more it could be a lot different."

Waikato Federated Farmers president Chris Lewis said his rain gauge measured 110mm at 7am . His parents' farm nearby measured 150mm, and the amount of rain and subsequent effects varied from district to district.

So far he had heard of no stock losses around the region, but it was possible it had occurred in places because the amount of rain hitting farms varied around the district.

"I think we have escaped pretty lightly for the amount of rain we have had."

Hauraki-Coromandel president Kevin Robinson said while river levels were swollen and many places had surface flooding, the region's farmers were generally coping well.

The weather has largely unaffected Fonterra's milk collection, with the dairy co-operative saying via twitter it had missed one pick up due to a road access issue.