Criminals are using the cover of the government's flagship energy policy to defraud money from homeowners.
The Green Deal offers loans to spend on energy-saving home improvement work with no upfront costs.
But trading standards officers have reported that cold callers are posing as Green Deal assessors while charging "administration fees".
Green Deal loans are only available through government contracted assessors who are identifiable through an allocated number.Quality mark
Mr Barker has now told the BBC that potential victims are being protected by the rules.
"We have very strong consumer protection, these are fraudsters and if we catch them we will come down on them like a tonne of bricks," he said.
"It would be terrible if we allowed these fraudsters to hijack the Green Deal and prevent it being offered to those at the bottom of the heap in society."
He added the situation would be monitored closely but his inclination was to continue with the policy of contacting people in poor-quality accommodation directly.
Consumers are advised to look out for the Green Deal Approved quality mark which proves assessors and installers are government registered.
The Energy Saving Advice Service can also confirm valid assessors on 0300 1231234.
For Full story visit: http://www.bbc.co.uk/news/business-22470012