A heavy rain warning issued for the Bay of Plenty and Rotorua remains in force today.

The MetService issued the orange warning on Thursday.

The region has already experienced heavy rain this morning, with downpours obsserved by SunLive readers around 1am.

In an updated warning today, the MetService says a  front preceded by a moist northerly flow is expected to move slowly east across New Zealand today bringing rain to much of the country.

"The heaviest rain is likely to affect the north of the North Island, and the north of the South Island.

"Localised downpours and thunderstorms are also possible for northern regions of the North Island.

"Watches for heavy rain are in force, and Rain Warnings for Bay of Plenty including Rotorua, and the Tasman District.

"People are advised to keep up to date with the latest forecasts."

Heavy Rain Warning - Orange

Area: Bay of Plenty and Rotorua
Period: 15 hours from 9am Fri 14 Jun to 12am Sat 15 Jun
Forecast: Expect another 60 to 90 mm of rain to accumulate on top of what has already fallen. Peak rates of 15 to 25 mm/h, but rates of 25 to 35 mm/h possible in localised downpours and thunderstorms.
Minimal chance of upgrading to a Red Warning.
Impact: Streams and rivers may rise rapidly. Surface flooding, slips, and difficult driving conditions possible.
Action: Clear your drains and gutters to prepare for heavy rain. Avoid low-lying areas and drive cautiously.