The Energy Minister's stressing Northland is a top concern for the Government

The region's experienced widespread power outages after a transmission tower fell down on Thursday morning, northwest of Auckland.

Transpower says its workers were carrying out maintenance at the time and has started an investigation.

The Electricity Authority is investigating, as is WorkSafe - who says it may take action if health and safety failings are identified.

Simeon Brown says this Government cares about Northland, which is a critical part of New Zealand.

He says they want to make sure the resilience of the community is a top priority.

Transpower expects power to be fully restored over the weekend - this afternoon at the earliest.