Consumer New Zealand is warning that an electrical device designed to save energy is potentially dangerous.
The device, which is called Go4Green Energy Smart, has now been banned from sale and from use.
Its manufacturers say it can reduce electricity costs by up to 10%.
The chief executive of Consumer New Zealand, Sue Chetwin, says testing found that claim to be misleading and owners are entitled to a full refund.
She says it merely stores electricity and remains live when removed from a wall socket.
Consumer New Zealand says people should disconnect the device, taking care not to touch the metal pins, and place it in a box or plastic container for a few days to discharge safely.
