Nelson - Tasman is facing millions of dollars of damage following last night's severe weather

Many properties are still without power in the region, with some state highways also closed.

Tasman's Mayor says it's the most devastating flooding he's seen and the wild weather marks the third weekend in a row of heavy rain in the region.

Minister for Emergency Management Mark Mitchell, says the damage will be in the millions without a doubt.

He says officials are carrying out assessments now and MPI officials were here last week assessing the damage to farm properties.