The Energy Minister says there are clear signs of a communications failure at Transpower.

Simeon Brown's given officials 12-weeks to report back on investigations into a transmission tower toppling last week leaving thousands in Northland without power.

Brown says there was a significant lack of information last Thursday after the pylon fell.

"There was no explanation given, publicly, by this entity until Monday - I think that was, frankly, unacceptable. And actually, they should be owning up to what happened and explaining that to the public."

Transpower says maintenance workers removed the nuts from three of the tower's legs, before it fell.

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