The Energy and Climate Change Committee has stepped up the pressure on energy suppliers to compensate consumers that have been mis-sold gas and electricity deals.
Its action follows price hikes by suppliers and was made in response to questions of whether consumers have paid too much for their energy.
The committee was told that up to 40 per cent of those persuaded to switch suppliers in doorstep stelling deals did not end up with a better solution.
The BBC News website reported that one supplier had recorded that 70 per cent of pre-payment customers who had switched to it had been persuaded to do so on their doorstep.
Four of the main energy suppliers are currently being investigated by Ofgem, the industry regulator, over this issue.
A campaign for a ban on cold-calling by energy salesmen has been launched by government watchdog Consumer Focus.
The issue has received increased attention following the prosecution of Scottish & Southern Energy by Surrey Trading Standards last May.