Electricity has been cut to seven Dunedin suburbs, allowing Delta staff to clear a fallen tree from power lines.

About 4000 homes and businesses have been affected by the power outages.

They only lasted about a minute, although the power supply was interrupted at least twice throughout the day.

The first cut was scheduled for about 9am.

Areas affected included Abbotsford, Burnside, Concord, Fairfield, Green Island, Ocean View and Waldronville.

Staff removed a tree which had fallen across high voltage power lines supplying the Green Island substation.

Power had to be redirected to nearby stations for that work to be done safely.