Authorities are keeping a close eye on Nelson and Tasman rivers as rain falls steadily across the region on already saturated ground.

On Tuesday afternoon, a Nelson Tasman Civil Defence post said an intense burst of rain in the hills near Belgrove had caused flooding from the Wai-iti River, between Belgrove and Wakefield.

It was recommended that stock in the area were moved to high ground, if possible, and motorists were asked to take extreme care.

A MetService orange rain warning is in place in the region on Tuesday, with a further 90 to 120 mm expected in areas west of Motueka, and a further 50mm to 70mm in Tasman and Nelson, east of Motueka until Tuesday night.

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The Tasman District Council said on Tuesday afternoon that the ranges behind Golden Bay recorded to 250 to 400mm rainfall from Monday night until 2pm on Tuesday and lowland areas recorded 30 to 80mm. The hills behind Nelson and Richmond recorded 40 to 70mm overnight to 2pm Tuesday.

The region has been drenched since last Friday, with downpours on Saturday leading to evacuations in parts of Tasman and Nelson and closing highways across the region.

Earlier on Tuesday afternoon a tree that fell on State Highway 6 on the Wakefield-Kohatu section, near Berrymans Rd, south-west of Nelson city.

Police responded to reports about the fallen tree at 1.30pm and arrived at the scene at 1.45pm.

A police spokesperson said cars had been giving way to each other as they passed the tree, and police were now assisting with traffic control until it was cleared.

Nelson Tasman Civil Defence said earlier that rivers in Golden Bay were slowly rising and expected to peak around 3pm. In Tasman district, the Riuwaka River was expected to peak around 5pm and the Motueka River around 8pm.

In Nelson, the Maitai River which flooded in parts after heavy rain at the weekend, was also expected to peak later this evening.

Civil Defence said all of the rivers and streams were expected to peak at annual flood levels or lower, but that could change if there were localised downpours.

Civil Defence asked motorists to take care on the roads because of surface flooding. It said if the rainfall intensities remained high in Golden Bay, surface flooding was possible around Bridges Hollow leading into Takaka and potentially the Waitapu Splash.

The MetService projections were for the rain to intensify in the early afternoon before easing this evening.