The planned demonstration of a device touted as being able to generate free power using the Earth's magnetic field has been put on hold after "technical difficulties".

Irish company Steorn claims that its Orbo machine will produce free, clean power to electrical generators.

The firm took out a full page advert in The Economist last year asking scientists to test its invention.

Steorn had planned a week-long demonstration of the technology at London's Kinetica Museum yesterday.

"We are experiencing some technical difficulties with the demo unit in London," said the company in a statement.

"Our initial assessment indicates that this is probably due to the intense heat from the camera lighting.

"We have commenced a technical assessment and will provide an update later today. As a consequence, Kinetica will not be open to the public today [5 July]. We apologise for this delay and appreciate your patience."

If the Orbo device lives up to the company's claims, it would violate the law of energy conservation which states that energy cannot be created or destroyed but migrates to different forms.

Steorn claims that power is generated using "time variant magneto-mechanical interactions" that occur naturally.

Orbo's efficacy has been greeted with worldwide scepticism. The panel of experts volunteering to study the technology are not due to report until the end of this year.