Robert Key, the frontbench trade and industry spokesman who was construction minister under John Major, said Wilson's responsibility for energy was so time-consuming that the construction industry was inevitably being neglected.
Key said: "As minister for energy he has to handle a white paper and the cabinet energy review. If he is so overstretched he should hand over his construction responsibilities to an undersecretary of state. I can understand why the construction industry feels so neglected."
Despite this, Key praised Wilson. He said: "Wilson is a very hard-working minister, to the point where I wonder what some of his DTI colleagues do all day. I have a great deal of sympathy with him."
Key added that the Whitehall shake-up after last year's general election, in which responsibility for construction moved from the DETR to the DTI, "appears to have been a misjudgment".
Wilson defended his role. He told Building that he was looking to spend more time on construction after the completion of a top-level energy review.
I can understand why the construction industry feels so neglected
Robert Key, ex-construction minister
He also defended construction's move to the DTI. He said: "The fundamental decision to move construction makes a lot of sense in the context of making the industry more competitive."
Wilson stressed that there was overlap between the energy and construction sides of his portfolio because the energy brief includes sustainable strategies. He said he has announced a number of demonstration or pilot projects incorporating solar power into housing developments, which combined both roles.
Key's comments came after Liberal Democrat spokesperson Don Foster lambasted Wilson's performance at the DTI.
Foster said: "I've seen little evidence of Wilson being on top of his brief. He doesn't seem to do very much. Clearly if you've got a minister who does little or nothing, he makes very few mistakes, but you don't get very far that way in the long run."
The criticism of Wilson's construction work rate follows similar complaints from leading industry figures.