Bay of Plenty residents are being urged to prepare for a soggy weekend, as a large low‑pressure system moves on to the country from Friday.

The system, which arrives in Fiordland early in the day, will push north through the weekend, with heavy rain expected to spread across much of the South Island before reaching the upper North Island by Saturday.

MetService has issued orange heavy rain warnings for parts of the West Coast, including Westland from midday on Friday and the Grey and Buller districts from 4pm, where 120 to 150mm of rain is forecast to fall through to Saturday morning.

The rain is also expected to spill east across the Southern Alps, with orange warnings in place for the Canterbury headwaters and a yellow heavy rain watch for the Otago headwaters.

Strong northwesterlies are forecast to develop ahead of the front, with a yellow strong wind watch for the Canterbury High Country from Friday afternoon until Saturday morning.

By Saturday, the front continues its march north, with periods of rain expected to reach parts of the North Island later in the day.

While the Bay of Plenty is not currently under any weather watches or warnings, showers are likely to increase from Saturday evening into Sunday as the system settles over the country.

MetService meteorologist Braydon White said people heading outdoors over the weekend should be prepared for changeable conditions.

“Those heading to the Warriors game on Saturday evening might want to pack a raincoat,” White said.

“With the potential for showers during the game, those looking to stay dry may need to break out the ponchos and brollies.”

Conditions remain unsettled into Sunday, with the broad low-pressure system lingering over New Zealand.

Several fronts are expected to rotate around it, bringing periods of rain interspersed with fine breaks for many regions, including the Bay of Plenty.

Looking ahead to the start of the new working week, the low is forecast to stick around, with winds shifting to the southeast and the possibility of persistent rain developing in eastern areas.

Motorists, trampers and those planning outdoor events are advised to keep a close eye on the forecast, as conditions may change quickly.