Bay of Plenty residents are being warned to prepare for another day of rain with a severe weather watch issued for the region.

The MetService says a deep low lying west of the South Island is moving slowly southwards and is forecast to cross Foveaux Strait tonight.

Today looks like another day to have the umbrella out. Photo: Rosalie Crawford.

Stevi-Lee playing in the mud yesterday. Photo: Lisa Adamson.

A strong moist northeast flow covers the South Island, but should gradually turn northerly as the low moves south.

A heavy rain warning is in force for Nelson, northern Marlborough and Westland.

Meanwhile, further bands of heavy showers and isolated thunderstorms are expected over the upper half of the North Island through to late Saturday, especially about Bay of Plenty.

The MetService says these thunderstorms and downpours are likely to be intense, but quite localised.

'This watch also covers possible short duration heavy rainfalls over Bay of Plenty through to Saturday evening.”

The Bay of Plenty has already seen a its fair share of rain this week, with tree and power lines downed on Thursday as the low crossed the North Island.

Friday wasn't much better as emergency services were called to numerous weather related calls in the Bay of Plenty.

The NZTA reports that State Highway 36, between Tauranga and Rotorua, at the Mangorewa Gorge remains closed due to a large slip.

The slip came down on Thursday blocking both sides of the highway. NZTA says the slip site is unstable and the road will be closed until further notice.

Read here to see photos of flooding and other damage caused by the severe weather.

Paengaroa Wet Fun Day.