Domestic heating oil cost 'to rise'
Mr Hendry said there had not been the expected drop in the price of the oil, which is used to heat some two million homes, schools and hospitals, over the summer months as he came under pressure from MPs to regulate the market.
Earlier this week, the Office of Fair Trading (OFT) said that it would continue to investigate allegations of market abuse after it found some price comparison websites were not independent and suppliers were charging a higher price than they were initially quoting.
But crucially the consumer watchdog said the market remained competitive and did not need price regulation.
He said: "What we have seen this summer is that we haven't seen the expected drop which one would find. I think after a year when we have had the unrest in the Middle East, it is clear that wholesale prices are higher and therefore it is understandable why that drop hasn't been so great.
"But we shouldn't fall into a trap therefore of assuming that they won't ramp up again into the very busy period before Christmas and the winter, so there is a real sense for consumers to order early to make sure that their tanks are as full as they can be at this point because one thing we can be certain about is that as we move towards winter, prices will go up further."
But MPs said it was time the Competition Commission intervened. Tory Skipton and Ripon MP Julian Smith said the OFT's report "let a number of companies who behaved pretty badly off the hook".
The DUP's Belfast North member Nigel Dodds said there was a "clear case for regulation" which needed to be looked at by the Government "very, very urgently".
Mr Hendry said the OFT was continuing to look at cases of market abuse and the suppliers would not be referred to the Competition Commission.
© 2011 Press Association